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 "$useValue". '
-                    'Install via the Fix button or check the spelling.'
+                ? strings.unknownCapInStore(useValue)
                 : didYouMean != null
-                    ? 'Unknown capability "$useValue". '
-                        'Did you mean "$didYouMean"?'
-                    : 'Unknown capability "$useValue". '
-                        'Not in the store — install locally with '
-                        '`fai install --link <path>` or check the spelling.';
+                    ? strings.unknownCapTypo(useValue, didYouMean)
+                    : strings.unknownCapNotInStore(useValue);
             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:
-              'Unknown $kind type "$value". '
-              'Use one of: ${kKnownTypes.join(", ")}.',
+          message: strings.unknownType(
+            kind,
+            value,
+            kKnownTypes.join(", "),
+          ),
           type: IssueType.warning,
         );
         out.add(issue);
         _bumpSeverity(nodeId, IssueType.warning);
-        // If the typo is within edit-distance two of a known
-        // type token, offer a one-click replace as the primary
-        // fix. The strip and tooltip render this as a button.
         final closest = _closestKnownType(value);
         if (closest != null) {
           _fixesByIssue[issue] = [
             ReplaceLineValueFix(
               line: entry.value.span.start.line,
               replacement: closest,
-              label: 'Change to "$closest"',
+              label: strings.fixChangeTo(closest),
             ),
           ];
         }