feat(studio): typed flow outputs + on-disk docs + UX polish

Documentation system (the original "whole docs system is broken"
complaint):
- Studio reads inline docs from disk via the new
  getInstalledModuleDocs RPC. No network, no auth, no provider
  lock-in.
- store.dart probes for MODULE.md eagerly when a module-detail
  sheet opens (a single file stat). The Documentation section
  only renders when the bundle actually shipped docs.
- Shared FaiTheme.markdownStyle helper used by Welcome's
  DocReaderSheet and Store's DocsPanel so every inline doc
  reads in the same typography. The shared style forces
  code.backgroundColor = transparent to suppress the per-span
  bands flutter_markdown's default code style draws on dark
  themes.

Flow run dialog:
- Run-button gating now strips the @version suffix from
  installed capabilities before the contains() check. Without
  this fix the button stayed disabled for every flow with
  dependencies, even after a successful install.
- Studio derives a MIME type from the picked file's extension
  (small per-suffix map; .pdf, .docx, .txt, .json, ...) and
  forwards it to the hub. Fixes "unsupported MIME type:
  application/octet-stream" from text.extract.
- Dialog title tracks the future's state: running -> "extract
  laeuft", success -> "extract -- Ergebnis", failure ->
  "extract -- fehlgeschlagen".
- Output rendering moved from String stringification to a
  sealed FlowOutput type (Text / Json / Bytes / File / Unknown).
  A new FaiFlowOutput widget dispatches per variant: markdown
  for text/markdown (heuristic), pretty JSON for proto Struct,
  inline image preview + Save-As for bytes, Open for file URIs.

Byte sizes:
- New humanBytes() helper renders 23.3 kB / 1.04 MB style values
  with three significant digits, matching Finder / GNOME Files.
  Wired into flow-card pills, picked-file readouts, and the
  bytes-payload preview line.

Signed-off-by: flemming-it <sf@flemming.it>
Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/l10n/app_de.arb

@@ -506,8 +506,23 @@
   "flowsRunButton": "Starten",
   "flowsRunningTitle": "{name} läuft",
   "@flowsRunningTitle": { "placeholders": { "name": { "type": "String" } } },
+  "flowsResultTitle": "{name} — Ergebnis",
+  "@flowsResultTitle": { "placeholders": { "name": { "type": "String" } } },
+  "flowsErrorTitle": "{name} — fehlgeschlagen",
+  "@flowsErrorTitle": { "placeholders": { "name": { "type": "String" } } },
   "flowsRunning": "Flow läuft…",
   "flowsNoOutputs": "Flow abgeschlossen ohne deklarierte Outputs.",
+  "flowsOutputUnknown": "Unbekannter Output-Payload-Typ.",
+  "flowsOutputBytesUnknownMime": "Binärdaten",
+  "flowsOutputSaveAs": "Speichern unter…",
+  "flowsOutputSaveAsTitle": "Flow-Output speichern",
+  "flowsOutputSavedAt": "Gespeichert: {path}",
+  "@flowsOutputSavedAt": { "placeholders": { "path": { "type": "String" } } },
+  "flowsOutputSaveFailed": "Speichern fehlgeschlagen: {error}",
+  "@flowsOutputSaveFailed": { "placeholders": { "error": { "type": "String" } } },
+  "flowsOutputOpen": "Öffnen",
+  "flowsOutputOpenFailed": "Öffnen fehlgeschlagen: {error}",
+  "@flowsOutputOpenFailed": { "placeholders": { "error": { "type": "String" } } },
 
   "approvalsTitle": "Freigaben",
   "approvalsTabPending": "Offen",

lib/l10n/app_en.arb

@@ -507,8 +507,23 @@
   "flowsRunButton": "Run",
   "flowsRunningTitle": "Running {name}",
   "@flowsRunningTitle": { "placeholders": { "name": { "type": "String" } } },
+  "flowsResultTitle": "{name} — result",
+  "@flowsResultTitle": { "placeholders": { "name": { "type": "String" } } },
+  "flowsErrorTitle": "{name} — failed",
+  "@flowsErrorTitle": { "placeholders": { "name": { "type": "String" } } },
   "flowsRunning": "Flow running…",
   "flowsNoOutputs": "Flow completed with no declared outputs.",
+  "flowsOutputUnknown": "Output payload variant not recognised.",
+  "flowsOutputBytesUnknownMime": "binary",
+  "flowsOutputSaveAs": "Save as…",
+  "flowsOutputSaveAsTitle": "Save flow output",
+  "flowsOutputSavedAt": "Saved to {path}",
+  "@flowsOutputSavedAt": { "placeholders": { "path": { "type": "String" } } },
+  "flowsOutputSaveFailed": "Save failed: {error}",
+  "@flowsOutputSaveFailed": { "placeholders": { "error": { "type": "String" } } },
+  "flowsOutputOpen": "Open",
+  "flowsOutputOpenFailed": "Open failed: {error}",
+  "@flowsOutputOpenFailed": { "placeholders": { "error": { "type": "String" } } },
 
   "approvalsTitle": "Approvals",
   "approvalsTabPending": "Pending",

lib/l10n/app_localizations.dart

@@ -2282,6 +2282,18 @@ abstract class AppLocalizations {
   /// **'Running {name}'**
   String flowsRunningTitle(String name);
 
+  /// No description provided for @flowsResultTitle.
+  ///
+  /// In en, this message translates to:
+  /// **'{name} — result'**
+  String flowsResultTitle(String name);
+
+  /// No description provided for @flowsErrorTitle.
+  ///
+  /// In en, this message translates to:
+  /// **'{name} — failed'**
+  String flowsErrorTitle(String name);
+
   /// No description provided for @flowsRunning.
   ///
   /// In en, this message translates to:
@@ -2294,6 +2306,54 @@ abstract class AppLocalizations {
   /// **'Flow completed with no declared outputs.'**
   String get flowsNoOutputs;
 
+  /// No description provided for @flowsOutputUnknown.
+  ///
+  /// In en, this message translates to:
+  /// **'Output payload variant not recognised.'**
+  String get flowsOutputUnknown;
+
+  /// No description provided for @flowsOutputBytesUnknownMime.
+  ///
+  /// In en, this message translates to:
+  /// **'binary'**
+  String get flowsOutputBytesUnknownMime;
+
+  /// No description provided for @flowsOutputSaveAs.
+  ///
+  /// In en, this message translates to:
+  /// **'Save as…'**
+  String get flowsOutputSaveAs;
+
+  /// No description provided for @flowsOutputSaveAsTitle.
+  ///
+  /// In en, this message translates to:
+  /// **'Save flow output'**
+  String get flowsOutputSaveAsTitle;
+
+  /// No description provided for @flowsOutputSavedAt.
+  ///
+  /// In en, this message translates to:
+  /// **'Saved to {path}'**
+  String flowsOutputSavedAt(String path);
+
+  /// No description provided for @flowsOutputSaveFailed.
+  ///
+  /// In en, this message translates to:
+  /// **'Save failed: {error}'**
+  String flowsOutputSaveFailed(String error);
+
+  /// No description provided for @flowsOutputOpen.
+  ///
+  /// In en, this message translates to:
+  /// **'Open'**
+  String get flowsOutputOpen;
+
+  /// No description provided for @flowsOutputOpenFailed.
+  ///
+  /// In en, this message translates to:
+  /// **'Open failed: {error}'**
+  String flowsOutputOpenFailed(String error);
+
   /// No description provided for @approvalsTitle.
   ///
   /// In en, this message translates to:

lib/l10n/app_localizations_de.dart

@@ -1308,12 +1308,52 @@ class AppLocalizationsDe extends AppLocalizations {
     return '$name läuft';
   }
 
+  @override
+  String flowsResultTitle(String name) {
+    return '$name — Ergebnis';
+  }
+
+  @override
+  String flowsErrorTitle(String name) {
+    return '$name — fehlgeschlagen';
+  }
+
   @override
   String get flowsRunning => 'Flow läuft…';
 
   @override
   String get flowsNoOutputs => 'Flow abgeschlossen ohne deklarierte Outputs.';
 
+  @override
+  String get flowsOutputUnknown => 'Unbekannter Output-Payload-Typ.';
+
+  @override
+  String get flowsOutputBytesUnknownMime => 'Binärdaten';
+
+  @override
+  String get flowsOutputSaveAs => 'Speichern unter…';
+
+  @override
+  String get flowsOutputSaveAsTitle => 'Flow-Output speichern';
+
+  @override
+  String flowsOutputSavedAt(String path) {
+    return 'Gespeichert: $path';
+  }
+
+  @override
+  String flowsOutputSaveFailed(String error) {
+    return 'Speichern fehlgeschlagen: $error';
+  }
+
+  @override
+  String get flowsOutputOpen => 'Öffnen';
+
+  @override
+  String flowsOutputOpenFailed(String error) {
+    return 'Öffnen fehlgeschlagen: $error';
+  }
+
   @override
   String get approvalsTitle => 'Freigaben';
 

lib/l10n/app_localizations_en.dart

@@ -1321,12 +1321,52 @@ class AppLocalizationsEn extends AppLocalizations {
     return 'Running $name';
   }
 
+  @override
+  String flowsResultTitle(String name) {
+    return '$name — result';
+  }
+
+  @override
+  String flowsErrorTitle(String name) {
+    return '$name — failed';
+  }
+
   @override
   String get flowsRunning => 'Flow running…';
 
   @override
   String get flowsNoOutputs => 'Flow completed with no declared outputs.';
 
+  @override
+  String get flowsOutputUnknown => 'Output payload variant not recognised.';
+
+  @override
+  String get flowsOutputBytesUnknownMime => 'binary';
+
+  @override
+  String get flowsOutputSaveAs => 'Save as…';
+
+  @override
+  String get flowsOutputSaveAsTitle => 'Save flow output';
+
+  @override
+  String flowsOutputSavedAt(String path) {
+    return 'Saved to $path';
+  }
+
+  @override
+  String flowsOutputSaveFailed(String error) {
+    return 'Save failed: $error';
+  }
+
+  @override
+  String get flowsOutputOpen => 'Open';
+
+  @override
+  String flowsOutputOpenFailed(String error) {
+    return 'Open failed: $error';
+  }
+
   @override
   String get approvalsTitle => 'Approvals';