feat(editor): localised analyzer/strip/run messages + monospace font fallback

Closes operator-reported issues around the text-tab font and
the English-only run + diagnostic surfaces.

  - **Real monospace everywhere**. The package never bundled
    JetBrains Mono as an asset (it relied on Studio's
    google_fonts pre-load), so a host that doesn't ship the
    font saw the YAML editor render in the system proportional
    default. New _monoTextStyle() pins fontFamilyFallback to a
    cross-platform monospace chain (Menlo / Consolas / Courier
    New / monospace) so the editor stays a grid in every host.
    Applied to the code field, gutter, diagnostic strip,
    issue rows, hover card, fix buttons, and the run tab's
    error box.

  - **Locale-aware analyzer messages**. New AnalyzerStrings
    adapter holds every string the analyzer emits, with an
    .english default + an .from(FlowEditorStrings) factory.
    FlowYamlCodeController.setCapabilityProviders takes the
    strings; FlowEditorPage wires them from the active locale.
    The analyzer's 'Unknown capability', 'Did you mean',
    'Not in the store — install locally with fai install
    --link', 'Unknown input/output type', YAML parse errors,
    and every quick-fix label (Install / Add source / Use /
    Change to) now flip to DE when the editor's locale is DE.

  - **Localised run + diagnostic chrome**. The bottom strip's
    'No issues', '2 errors · 1 warning', 'Copy all'; the
    issue row's L-prefix + Copy tooltip; the hover card's
    L-prefix + Copy tooltip; the run-block tooltip + inline
    message ('2 Fehler verhindern den Lauf · siehe
    Diagnose-Leiste unten'); the step-row 'awaiting approval'
    suffix; the CopyableErrorBox's Copy / Copied tooltip —
    all now flow through FlowEditorStrings.

Bumped to 0.20.0.

Signed-off-by: flemming-it <sf@flemming.it>

lib/src/flow_analyzer.dart

@@ -20,6 +20,7 @@
 import 'package:flutter_code_editor/flutter_code_editor.dart';
 import 'package:yaml/yaml.dart';
 
+import 'l10n.dart';
 import 'quick_fix.dart';
 import 'wire_colors.dart';
 
@@ -59,9 +60,15 @@ class FlowAnalyzer extends AbstractAnalyzer {
   /// [kOutputsNodeId] sentinels.
   final Map<String, IssueType> _stepSeverity = {};
 
+  /// Localised string builders the analyzer pipes its messages
+  /// through. Default is English so the analyzer behaves the
+  /// same in tests + host-less callers.
+  final AnalyzerStrings strings;
+
   FlowAnalyzer({
     required this.availableCapabilities,
     this.storeCapabilities,
+    this.strings = AnalyzerStrings.english,
   });
 
   /// Read-only view of the fixes computed during the last
@@ -115,14 +122,18 @@ class FlowAnalyzer extends AbstractAnalyzer {
       issues.add(
         Issue(
           line: e.span?.start.line ?? 0,
-          message: 'YAML: ${e.message}',
+          message: strings.yamlError(e.message),
           type: IssueType.error,
         ),
       );
       return AnalysisResult(issues: issues);
     } catch (e) {
       issues.add(
-        Issue(line: 0, message: 'YAML: $e', type: IssueType.error),
+        Issue(
+          line: 0,
+          message: strings.yamlError(e.toString()),
+          type: IssueType.error,
+        ),
       );
       return AnalysisResult(issues: issues);
     }
@@ -159,16 +170,12 @@ class FlowAnalyzer extends AbstractAnalyzer {
 
             // Tailor the message: "unknown" reads identical in
             // both cases, but the recovery line nudges toward
-            // the right action.
+            // the right action. Localised via [strings].
             final message = inStore
-                ? 'Unknown capability "$useValue". '
+                ? strings.unknownCapInStore(useValue)
-                    'Install via the Fix button or check the spelling.'
                 : didYouMean != null
-                    ? 'Unknown capability "$useValue". '
+                    ? strings.unknownCapTypo(useValue, didYouMean)
-                        'Did you mean "$didYouMean"?'
+                    : strings.unknownCapNotInStore(useValue);
-                    : 'Unknown capability "$useValue". '
-                        'Not in the store — install locally with '
-                        '`fai install --link <path>` or check the spelling.';
             final issue = Issue(
               line: issueLine,
               message: message,
@@ -192,7 +199,7 @@ class FlowAnalyzer extends AbstractAnalyzer {
                 ReplaceLineValueFix(
                   line: issueLine,
                   replacement: fullReplacement,
-                  label: 'Use "$fullReplacement"',
+                  label: strings.fixUseInstead(fullReplacement),
                 ),
               );
             }
@@ -200,20 +207,14 @@ class FlowAnalyzer extends AbstractAnalyzer {
               fixes.add(
                 InstallCapabilityFix(
                   capability: useValue,
-                  label: 'Install $useValue',
+                  label: strings.fixInstallCap(useValue),
                 ),
               );
             } else if (didYouMean == null) {
-              // Not in store + no near-miss spelling — give the
-              // operator a path to register the module they
-              // actually have (local clone, internal URL, …).
-              // Hidden behind the "Did you mean" suggestion when
-              // present so the suggested fix stays the primary
-              // action.
               fixes.add(
                 AddModuleSourceFix(
                   capability: useValue,
-                  label: 'Add source for $useValue…',
+                  label: strings.fixAddSource(useValue),
                 ),
               );
             }
@@ -226,13 +227,13 @@ class FlowAnalyzer extends AbstractAnalyzer {
 
       _checkFieldTypes(
         doc['inputs'],
-        'input',
+        strings.inputKind(),
         issues,
         nodeId: kInputsNodeId,
       );
       _checkFieldTypes(
         doc['outputs'],
-        'output',
+        strings.outputKind(),
         issues,
         nodeId: kOutputsNodeId,
       );
@@ -278,23 +279,22 @@ class FlowAnalyzer extends AbstractAnalyzer {
       if (!kKnownTypes.contains(value)) {
         final issue = Issue(
           line: entry.value.span.start.line,
-          message:
+          message: strings.unknownType(
-              'Unknown $kind type "$value". '
+            kind,
-              'Use one of: ${kKnownTypes.join(", ")}.',
+            value,
+            kKnownTypes.join(", "),
+          ),
           type: IssueType.warning,
         );
         out.add(issue);
         _bumpSeverity(nodeId, IssueType.warning);
-        // If the typo is within edit-distance two of a known
-        // type token, offer a one-click replace as the primary
-        // fix. The strip and tooltip render this as a button.
         final closest = _closestKnownType(value);
         if (closest != null) {
           _fixesByIssue[issue] = [
             ReplaceLineValueFix(
               line: entry.value.span.start.line,
               replacement: closest,
-              label: 'Change to "$closest"',
+              label: strings.fixChangeTo(closest),
             ),
           ];
         }

lib/src/flow_editor_page.dart

@@ -137,6 +137,7 @@ class _FlowEditorPageState extends State<FlowEditorPage>
     _controller.codeController.setCapabilityProviders(
       available: () => widget.availableCapabilities,
       store: () => widget.storeCapabilities,
+      strings: AnalyzerStrings.from(_l),
     );
     _controller.addListener(_onCtrlChanged);
     _controller.codeController.hoverRequest.addListener(_onHoverChanged);
@@ -175,6 +176,7 @@ class _FlowEditorPageState extends State<FlowEditorPage>
     _hoverEntry = OverlayEntry(
       builder: (ctx) => _IssueHoverCard(
         request: req,
+        strings: _l,
         onApplyFix: _applyQuickFix,
         onEnter: _controller.codeController.cancelHoverDismiss,
         onExit: _controller.codeController.scheduleHoverDismiss,
@@ -205,6 +207,7 @@ class _FlowEditorPageState extends State<FlowEditorPage>
           _controller.codeController.setCapabilityProviders(
             available: () => newCaps,
             store: () => widget.storeCapabilities,
+            strings: AnalyzerStrings.from(_l),
           );
           await _controller.codeController.reanalyze();
         }
@@ -217,6 +220,7 @@ class _FlowEditorPageState extends State<FlowEditorPage>
           _controller.codeController.setCapabilityProviders(
             available: () => newCaps,
             store: () => widget.storeCapabilities,
+            strings: AnalyzerStrings.from(_l),
           );
           await _controller.codeController.reanalyze();
         }
@@ -578,6 +582,7 @@ outputs:
         // the message + quick-fix buttons.
         _DiagnosticStrip(
           controller: _controller.codeController,
+          strings: _l,
           onApplyFix: _applyQuickFix,
         ),
       ],
@@ -719,9 +724,15 @@ outputs:
   }
 
   Widget _textTab(ThemeData theme) {
-    final mono = TextStyle(
+    // The editor itself doesn't bundle JetBrains Mono as an
-      fontFamily: 'JetBrains Mono',
+    // asset (Studio preloads it via google_fonts). When the
-      fontSize: 13,
+    // host isn't Studio, Flutter would fall back to a
+    // proportional default and the code would line up like
+    // ransom-note prose. _monoTextStyle's fontFamilyFallback
+    // pins the chain to the system monospace stack so a YAML
+    // grid stays a grid in every host.
+    final mono = _monoTextStyle(
+      size: 13,
       height: 1.45,
       color: theme.colorScheme.onSurface,
     );
@@ -757,11 +768,7 @@ outputs:
   Map<String, TextStyle> _yamlStyle(ThemeData theme) {
     final cs = theme.colorScheme;
     final isDark = theme.brightness == Brightness.dark;
-    final monoBase = TextStyle(
+    final monoBase = _monoTextStyle(size: 13, height: 1.45);
-      fontFamily: 'JetBrains Mono',
-      fontSize: 13,
-      height: 1.45,
-    );
     // Pick clearly-distinguished hues so keys, strings,
     // numbers, anchors, and comments don't blur into each
     // other. We derive accents from the active ColorScheme
@@ -1002,8 +1009,7 @@ class _TabActionStrip extends StatelessWidget {
                 const SizedBox(width: FaiSpace.sm),
                 Tooltip(
                   message: errorCount > 0
-                      ? '$errorCount error${errorCount == 1 ? '' : 's'} '
+                      ? strings.runErrorsBlockTooltip(errorCount)
-                            'prevent the run — fix them first'
                       : '',
                   child: FilledButton.icon(
                     onPressed: onRun,
@@ -1277,11 +1283,44 @@ class _NewFlowDialogState extends State<_NewFlowDialog> {
 /// the trackpad-only operator. When the analyzer attaches a
 /// `QuickFix` to an issue, the row also renders an action
 /// button (e.g. "Install <cap>" or "Change to \"bytes\"").
+/// Build a TextStyle that prefers `JetBrains Mono` (Studio
+/// preloads it via `google_fonts`) but falls back to the
+/// system's generic `monospace` family when the bundled font
+/// isn't registered — which is what happens when this package
+/// is hosted by something other than Studio. Without the
+/// fallback the field rendered with the default proportional
+/// font and code lined up like ransom-note prose.
+TextStyle _monoTextStyle({
+  required double size,
+  Color? color,
+  FontWeight? weight,
+  double? letterSpacing,
+  double? height,
+}) {
+  return TextStyle(
+    fontFamily: 'JetBrains Mono',
+    fontFamilyFallback: const [
+      'JetBrainsMono Nerd Font',
+      'Menlo',
+      'Consolas',
+      'Courier New',
+      'monospace',
+    ],
+    fontSize: size,
+    color: color,
+    fontWeight: weight,
+    letterSpacing: letterSpacing,
+    height: height,
+  );
+}
+
 class _DiagnosticStrip extends StatefulWidget {
   final FlowYamlCodeController controller;
+  final FlowEditorStrings strings;
   final Future<void> Function(QuickFix) onApplyFix;
   const _DiagnosticStrip({
     required this.controller,
+    required this.strings,
     required this.onApplyFix,
   });
 
@@ -1324,7 +1363,9 @@ class _DiagnosticStripState extends State<_DiagnosticStrip> {
   String _formatAll(List<Issue> issues) {
     final buf = StringBuffer();
     for (final i in issues) {
-      buf.writeln('L${i.line + 1}: ${i.message}');
+      buf.writeln(
+        '${widget.strings.diagnosticLinePrefix(i.line + 1)}: ${i.message}',
+      );
     }
     return buf.toString().trimRight();
   }
@@ -1354,12 +1395,11 @@ class _DiagnosticStripState extends State<_DiagnosticStrip> {
           ),
         ),
         child: Text(
-          'No issues',
+          widget.strings.diagnosticNoIssues,
-          style: TextStyle(
+          style: _monoTextStyle(
-            fontFamily: 'JetBrains Mono',
+            size: 10,
-            fontSize: 10,
-            letterSpacing: 0.4,
             color: theme.colorScheme.onSurfaceVariant.withValues(alpha: 0.6),
+            letterSpacing: 0.4,
           ),
         ),
       );
@@ -1402,27 +1442,25 @@ class _DiagnosticStripState extends State<_DiagnosticStrip> {
                     const SizedBox(width: 8),
                     Text(
                       _summary(errorCount, warnCount),
-                      style: TextStyle(
+                      style: _monoTextStyle(
-                        fontFamily: 'JetBrains Mono',
+                        size: 11,
-                        fontSize: 11,
+                        weight: FontWeight.w600,
-                        fontWeight: FontWeight.w600,
                         color: tone,
                       ),
                     ),
                     const SizedBox(width: 8),
                     Expanded(
                       child: SelectableText(
-                        'L${issues.first.line + 1}: ${issues.first.message}',
+                        '${widget.strings.diagnosticLinePrefix(issues.first.line + 1)}: ${issues.first.message}',
                         maxLines: 1,
-                        style: TextStyle(
+                        style: _monoTextStyle(
-                          fontFamily: 'JetBrains Mono',
+                          size: 11,
-                          fontSize: 11,
                           color: theme.colorScheme.onSurface,
                         ),
                       ),
                     ),
                     IconButton(
-                      tooltip: 'Copy all',
+                      tooltip: widget.strings.diagnosticCopyAll,
                       icon: const Icon(Icons.content_copy, size: 14),
                       visualDensity: VisualDensity.compact,
                       onPressed: () => _copy(_formatAll(issues)),
@@ -1453,10 +1491,12 @@ class _DiagnosticStripState extends State<_DiagnosticStrip> {
                           issue: issue,
                           fixes: widget.controller.fixesFor(issue),
                           tone: _toneForIssue(issue.type, theme),
+                          strings: widget.strings,
                           busy: _busy,
                           onApplyFix: _runFix,
-                          onCopy: () =>
+                          onCopy: () => _copy(
-                              _copy('L${issue.line + 1}: ${issue.message}'),
+                            '${widget.strings.diagnosticLinePrefix(issue.line + 1)}: ${issue.message}',
+                          ),
                         ),
                     ],
                   ),
@@ -1471,9 +1511,9 @@ class _DiagnosticStripState extends State<_DiagnosticStrip> {
 
   String _summary(int errors, int warnings) {
     final parts = <String>[];
-    if (errors > 0) parts.add('$errors error${errors == 1 ? '' : 's'}');
+    if (errors > 0) parts.add(widget.strings.diagnosticErrors(errors));
     if (warnings > 0) {
-      parts.add('$warnings warning${warnings == 1 ? '' : 's'}');
+      parts.add(widget.strings.diagnosticWarnings(warnings));
     }
     return parts.join(' · ');
   }
@@ -1487,6 +1527,7 @@ class _IssueRow extends StatelessWidget {
   final Issue issue;
   final List<QuickFix> fixes;
   final Color tone;
+  final FlowEditorStrings strings;
   final Map<QuickFix, bool> busy;
   final Future<void> Function(QuickFix) onApplyFix;
   final VoidCallback onCopy;
@@ -1495,6 +1536,7 @@ class _IssueRow extends StatelessWidget {
     required this.issue,
     required this.fixes,
     required this.tone,
+    required this.strings,
     required this.busy,
     required this.onApplyFix,
     required this.onCopy,
@@ -1517,10 +1559,9 @@ class _IssueRow extends StatelessWidget {
           SizedBox(
             width: 42,
             child: Text(
-              'L${issue.line + 1}',
+              strings.diagnosticLinePrefix(issue.line + 1),
-              style: TextStyle(
+              style: _monoTextStyle(
-                fontFamily: 'JetBrains Mono',
+                size: 11,
-                fontSize: 11,
                 color: theme.colorScheme.onSurfaceVariant,
               ),
             ),
@@ -1528,16 +1569,15 @@ class _IssueRow extends StatelessWidget {
           Expanded(
             child: SelectableText(
               issue.message,
-              style: TextStyle(
+              style: _monoTextStyle(
-                fontFamily: 'JetBrains Mono',
+                size: 11,
-                fontSize: 11,
                 color: theme.colorScheme.onSurface,
               ),
             ),
           ),
           const SizedBox(width: 8),
           IconButton(
-            tooltip: 'Copy',
+            tooltip: strings.runCopy,
             icon: const Icon(Icons.content_copy, size: 13),
             visualDensity: VisualDensity.compact,
             padding: EdgeInsets.zero,
@@ -1557,10 +1597,7 @@ class _IssueRow extends StatelessWidget {
                   : const Icon(Icons.auto_fix_high, size: 13),
               label: Text(
                 fix.label,
-                style: const TextStyle(
+                style: _monoTextStyle(size: 11),
-                  fontFamily: 'JetBrains Mono',
-                  fontSize: 11,
-                ),
               ),
               style: FilledButton.styleFrom(
                 visualDensity: VisualDensity.compact,
@@ -1586,12 +1623,14 @@ class _IssueRow extends StatelessWidget {
 /// tooltip so action buttons stay clickable.
 class _IssueHoverCard extends StatelessWidget {
   final IssueHoverRequest request;
+  final FlowEditorStrings strings;
   final Future<void> Function(QuickFix) onApplyFix;
   final VoidCallback onEnter;
   final VoidCallback onExit;
 
   const _IssueHoverCard({
     required this.request,
+    required this.strings,
     required this.onApplyFix,
     required this.onEnter,
     required this.onExit,
@@ -1666,10 +1705,9 @@ class _IssueHoverCard extends StatelessWidget {
                     ),
                     const SizedBox(width: 8),
                     Text(
-                      'L${request.line + 1}',
+                      strings.diagnosticLinePrefix(request.line + 1),
-                      style: TextStyle(
+                      style: _monoTextStyle(
-                        fontFamily: 'JetBrains Mono',
+                        size: 11,
-                        fontSize: 11,
                         color: theme.colorScheme.onSurfaceVariant,
                       ),
                     ),
@@ -1677,22 +1715,21 @@ class _IssueHoverCard extends StatelessWidget {
                     Expanded(
                       child: SelectableText(
                         request.message,
-                        style: TextStyle(
+                        style: _monoTextStyle(
-                          fontFamily: 'JetBrains Mono',
+                          size: 12,
-                          fontSize: 12,
                           color: theme.colorScheme.onSurface,
                         ),
                       ),
                     ),
                     IconButton(
-                      tooltip: 'Copy',
+                      tooltip: strings.runCopy,
                       icon: const Icon(Icons.content_copy, size: 14),
                       visualDensity: VisualDensity.compact,
                       onPressed: () {
                         Clipboard.setData(
                           ClipboardData(
                             text:
-                                'L${request.line + 1}: ${request.message}',
+                                '${strings.diagnosticLinePrefix(request.line + 1)}: ${request.message}',
                           ),
                         );
                       },
@@ -1711,10 +1748,7 @@ class _IssueHoverCard extends StatelessWidget {
                           icon: const Icon(Icons.auto_fix_high, size: 13),
                           label: Text(
                             fix.label,
-                            style: const TextStyle(
+                            style: _monoTextStyle(size: 11),
-                              fontFamily: 'JetBrains Mono',
-                              fontSize: 11,
-                            ),
                           ),
                           style: FilledButton.styleFrom(
                             visualDensity: VisualDensity.compact,

lib/src/flow_yaml_controller.dart

@@ -23,6 +23,7 @@ import 'package:flutter_code_editor/flutter_code_editor.dart';
 import 'package:highlight/languages/yaml.dart';
 
 import 'flow_analyzer.dart';
+import 'l10n.dart';
 import 'quick_fix.dart';
 import 'wire_colors.dart';
 
@@ -30,6 +31,7 @@ class FlowYamlCodeController extends CodeController {
   FlowYamlCodeController({
     List<String> Function()? availableCapabilities,
     List<String> Function()? storeCapabilities,
+    AnalyzerStrings analyzerStrings = AnalyzerStrings.english,
   }) : super(
          text: '',
          language: yaml,
@@ -37,20 +39,23 @@ class FlowYamlCodeController extends CodeController {
            availableCapabilities:
                availableCapabilities ?? (() => const <String>[]),
            storeCapabilities: storeCapabilities,
+           strings: analyzerStrings,
          ),
        );
 
-  /// Set both capability providers in one go. Re-creating the
+  /// Set capability providers AND the analyzer's locale-aware
-  /// analyzer is the simplest way to flip both closures without
+  /// message strings. Re-creating the analyzer is the simplest
-  /// risking a stale storeCapabilities reference inside an old
+  /// way to flip these atomically without risking a stale
-  /// FlowAnalyzer instance.
+  /// closure or stale strings inside an old FlowAnalyzer.
   void setCapabilityProviders({
     required List<String> Function() available,
     List<String> Function()? store,
+    AnalyzerStrings? strings,
   }) {
     analyzer = FlowAnalyzer(
       availableCapabilities: available,
       storeCapabilities: store,
+      strings: strings ?? AnalyzerStrings.english,
     );
   }
 

lib/src/l10n.dart

@@ -145,4 +145,161 @@ class FlowEditorStrings {
   String get endpointExpression => _t('Expression', 'Ausdruck');
   String get endpointAdd => _t('Add', 'Hinzufügen');
   String get endpointRemove => _t('Remove', 'Entfernen');
+
+  // Run-tab step row + error block.
+  String get runAwaitingApproval =>
+      _t('awaiting approval', 'wartet auf Freigabe');
+  String get runCopy => _t('Copy', 'Kopieren');
+  String get runCopied => _t('Copied', 'Kopiert');
+  String runErrorsBlockRun(int n) => _t(
+        '$n error${n == 1 ? '' : 's'} prevent the run',
+        '$n ${n == 1 ? 'Fehler verhindert' : 'Fehler verhindern'} den Lauf',
+      );
+  String get runErrorsBlockHint => _t(
+        'check the diagnostic strip',
+        'siehe Diagnose-Leiste unten',
+      );
+  String runErrorsBlockTooltip(int n) => _t(
+        '$n error${n == 1 ? '' : 's'} prevent the run — fix them first',
+        '$n ${n == 1 ? 'Fehler verhindert' : 'Fehler verhindern'} den Lauf — '
+            'bitte zuerst beheben',
+      );
+
+  // Bottom diagnostic strip + hover card.
+  String get diagnosticNoIssues => _t('No issues', 'Keine Probleme');
+  String diagnosticErrors(int n) =>
+      _t('$n error${n == 1 ? '' : 's'}', '$n Fehler');
+  String diagnosticWarnings(int n) =>
+      _t('$n warning${n == 1 ? '' : 's'}', '$n Warnungen');
+  String get diagnosticCopyAll => _t('Copy all', 'Alle kopieren');
+  String diagnosticLinePrefix(int line) => 'L$line';
+
+  // Analyzer-emitted messages — used by FlowAnalyzer via the
+  // [AnalyzerStrings] adapter below so the same strings can be
+  // localized centrally.
+  String analyzerUnknownCapInStore(String cap) => _t(
+        'Unknown capability "$cap". '
+            'Install via the Fix button or check the spelling.',
+        'Unbekannte Capability "$cap". '
+            'Per Fix-Button installieren oder Tippfehler prüfen.',
+      );
+  String analyzerUnknownCapTypo(String cap, String suggestion) => _t(
+        'Unknown capability "$cap". Did you mean "$suggestion"?',
+        'Unbekannte Capability "$cap". Meintest du "$suggestion"?',
+      );
+  String analyzerUnknownCapNotInStore(String cap) => _t(
+        'Unknown capability "$cap". '
+            'Not in the store — install locally with '
+            '`fai install --link <path>` or check the spelling.',
+        'Unbekannte Capability "$cap". '
+            'Nicht im Store — lokal mit '
+            '`fai install --link <pfad>` installieren oder Tippfehler prüfen.',
+      );
+  String analyzerInputKind() => _t('input', 'Eingabe');
+  String analyzerOutputKind() => _t('output', 'Ausgabe');
+  String analyzerUnknownType(String kind, String value, String validList) =>
+      _t(
+        'Unknown $kind type "$value". Use one of: $validList.',
+        'Unbekannter $kind-Typ "$value". Erlaubt sind: $validList.',
+      );
+  String analyzerYamlError(String detail) => _t('YAML: $detail', 'YAML: $detail');
+
+  // Quick-fix button labels.
+  String fixInstallCap(String cap) => _t('Install $cap', '$cap installieren');
+  String fixAddSource(String cap) =>
+      _t('Add source for $cap…', 'Quelle für $cap hinzufügen…');
+  String fixUseInstead(String name) =>
+      _t('Use "$name"', '"$name" verwenden');
+  String fixChangeTo(String name) =>
+      _t('Change to "$name"', 'Auf "$name" ändern');
+}
+
+/// Subset of [FlowEditorStrings] the analyzer consumes. Kept as
+/// a separate adapter so a test or alternate host can plug in
+/// a custom string-builder without owning the whole Editor
+/// string table.
+class AnalyzerStrings {
+  final String Function(String cap) unknownCapInStore;
+  final String Function(String cap, String suggestion) unknownCapTypo;
+  final String Function(String cap) unknownCapNotInStore;
+  final String Function(String kind, String value, String validList)
+      unknownType;
+  final String Function() inputKind;
+  final String Function() outputKind;
+  final String Function(String detail) yamlError;
+
+  final String Function(String cap) fixInstallCap;
+  final String Function(String cap) fixAddSource;
+  final String Function(String name) fixUseInstead;
+  final String Function(String name) fixChangeTo;
+
+  const AnalyzerStrings({
+    required this.unknownCapInStore,
+    required this.unknownCapTypo,
+    required this.unknownCapNotInStore,
+    required this.unknownType,
+    required this.inputKind,
+    required this.outputKind,
+    required this.yamlError,
+    required this.fixInstallCap,
+    required this.fixAddSource,
+    required this.fixUseInstead,
+    required this.fixChangeTo,
+  });
+
+  /// Build an [AnalyzerStrings] from the editor's
+  /// [FlowEditorStrings] — every host that uses the editor
+  /// gets analyzer messages in the same language as the rest
+  /// of the UI for free.
+  factory AnalyzerStrings.from(FlowEditorStrings s) => AnalyzerStrings(
+        unknownCapInStore: s.analyzerUnknownCapInStore,
+        unknownCapTypo: s.analyzerUnknownCapTypo,
+        unknownCapNotInStore: s.analyzerUnknownCapNotInStore,
+        unknownType: s.analyzerUnknownType,
+        inputKind: s.analyzerInputKind,
+        outputKind: s.analyzerOutputKind,
+        yamlError: s.analyzerYamlError,
+        fixInstallCap: s.fixInstallCap,
+        fixAddSource: s.fixAddSource,
+        fixUseInstead: s.fixUseInstead,
+        fixChangeTo: s.fixChangeTo,
+      );
+
+  /// Built-in English defaults — used by tests + by the
+  /// editor when no host has wired strings yet. Identical to
+  /// FlowEditorStrings(en) output so behaviour matches across
+  /// the two code paths.
+  static const AnalyzerStrings english = AnalyzerStrings._english();
+
+  const AnalyzerStrings._english()
+      : unknownCapInStore = _enUnknownCapInStore,
+        unknownCapTypo = _enUnknownCapTypo,
+        unknownCapNotInStore = _enUnknownCapNotInStore,
+        unknownType = _enUnknownType,
+        inputKind = _enInputKind,
+        outputKind = _enOutputKind,
+        yamlError = _enYamlError,
+        fixInstallCap = _enFixInstall,
+        fixAddSource = _enFixAddSource,
+        fixUseInstead = _enFixUse,
+        fixChangeTo = _enFixChange;
+
+  static String _enUnknownCapInStore(String cap) =>
+      'Unknown capability "$cap". '
+      'Install via the Fix button or check the spelling.';
+  static String _enUnknownCapTypo(String cap, String suggestion) =>
+      'Unknown capability "$cap". Did you mean "$suggestion"?';
+  static String _enUnknownCapNotInStore(String cap) =>
+      'Unknown capability "$cap". '
+      'Not in the store — install locally with '
+      '`fai install --link <path>` or check the spelling.';
+  static String _enUnknownType(String kind, String value, String validList) =>
+      'Unknown $kind type "$value". Use one of: $validList.';
+  static String _enInputKind() => 'input';
+  static String _enOutputKind() => 'output';
+  static String _enYamlError(String detail) => 'YAML: $detail';
+  static String _enFixInstall(String cap) => 'Install $cap';
+  static String _enFixAddSource(String cap) => 'Add source for $cap…';
+  static String _enFixUse(String name) => 'Use "$name"';
+  static String _enFixChange(String name) => 'Change to "$name"';
 }

lib/src/widgets/run_tab.dart

@@ -183,7 +183,10 @@ class _RunTabState extends State<RunTab> {
           if (_error != null) ...[
             const SizedBox(height: FaiSpace.lg),
             _section(theme, strings.runTitleFailed),
-            _CopyableErrorBox(text: _error.toString()),
+            _CopyableErrorBox(
+              text: _error.toString(),
+              strings: widget.strings,
+            ),
           ],
         ],
       ),
@@ -300,6 +303,7 @@ class _RunTabState extends State<RunTab> {
   }
 
   Widget _stepRow(ThemeData theme, String id, _StepState state) {
+    final strings = widget.strings;
     final IconData glyph;
     final Color color;
     String suffix = '';
@@ -317,7 +321,7 @@ class _RunTabState extends State<RunTab> {
       case _StepKind.awaiting:
         glyph = Icons.pause_circle_outline;
         color = theme.colorScheme.tertiary;
-        suffix = '  awaiting approval';
+        suffix = '  ${strings.runAwaitingApproval}';
     }
     final isError = state.kind == _StepKind.error &&
         state.error != null &&
@@ -347,7 +351,10 @@ class _RunTabState extends State<RunTab> {
             const SizedBox(height: 4),
             Padding(
               padding: const EdgeInsets.only(left: 24),
-              child: _CopyableErrorBox(text: state.error!),
+              child: _CopyableErrorBox(
+                text: state.error!,
+                strings: widget.strings,
+              ),
             ),
           ],
         ],
@@ -365,9 +372,7 @@ class _RunTabState extends State<RunTab> {
     return Row(
       children: [
         Tooltip(
-          message: blocked
+          message: blocked ? strings.runErrorsBlockTooltip(errors) : '',
-              ? '$errors error${errors == 1 ? '' : 's'} prevent the run'
-              : '',
           child: FilledButton.icon(
             onPressed: _running || widget.driver == null || blocked
                 ? null
@@ -389,8 +394,8 @@ class _RunTabState extends State<RunTab> {
           const SizedBox(width: FaiSpace.sm),
           Flexible(
             child: Text(
-              '$errors error${errors == 1 ? '' : 's'} prevent the run · '
+              '${strings.runErrorsBlockRun(errors)} · '
-              'check the diagnostic strip',
+              '${strings.runErrorsBlockHint}',
               style: theme.textTheme.bodySmall?.copyWith(
                 color: theme.colorScheme.error,
               ),
@@ -619,7 +624,8 @@ class _StepState {
 /// so flow_editor doesn't depend on Studio internals.
 class _CopyableErrorBox extends StatefulWidget {
   final String text;
-  const _CopyableErrorBox({required this.text});
+  final FlowEditorStrings strings;
+  const _CopyableErrorBox({required this.text, required this.strings});
 
   @override
   State<_CopyableErrorBox> createState() => _CopyableErrorBoxState();
@@ -661,7 +667,8 @@ class _CopyableErrorBoxState extends State<_CopyableErrorBox> {
           Align(
             alignment: Alignment.centerRight,
             child: Tooltip(
-              message: _justCopied ? 'Copied' : 'Copy',
+              message:
+                  _justCopied ? widget.strings.runCopied : widget.strings.runCopy,
               child: IconButton(
                 icon: Icon(
                   _justCopied ? Icons.check : Icons.content_copy,
@@ -682,6 +689,12 @@ class _CopyableErrorBoxState extends State<_CopyableErrorBox> {
                   widget.text,
                   style: TextStyle(
                     fontFamily: 'JetBrains Mono',
+                    fontFamilyFallback: const [
+                      'Menlo',
+                      'Consolas',
+                      'Courier New',
+                      'monospace',
+                    ],
                     fontSize: 12,
                     color: theme.colorScheme.onErrorContainer,
                   ),

pubspec.yaml

@@ -1,6 +1,6 @@
 name: fai_studio_flow_editor
 description: Swappable inline YAML editor for F∆I Studio flows.
-version: 0.19.0
+version: 0.20.0
 publish_to: 'none'
 repository: https://git.flemming.ai/fai/studio-flow-editor