feat(studio): localise Settings sidebar + add inline help docs + Approvals doc

Three operator-UX gaps closed:

  - Settings dialog's six-category sidebar (General / Appearance /
    System AI / Integrations / Security / Maintenance) was
    hardcoded English; now flows through AppLocalizations
    ("Allgemein" / "Darstellung" / "System-KI" / "Integrationen" /
    "Sicherheit" / "Wartung"). Same for the per-panel title +
    description.
  - Per-channel daemon-action labels ('enable autostart' /
    'disable autostart' / 'daemon restart' etc.) and the
    OK / Failed result line in the toast also moved to l10n,
    so the system-action feedback reads as one language.
  - New 'Approvals' doc bundle (en + de) under assets/docs/,
    registered as a fifth doc card on Welcome plus exposed via
    the new public  helper. The
    Approvals, Audit and Doctor app-bars grow a Help icon button
    next to Refresh that opens the matching doc in the existing
    bottom-sheet reader — no extra screen, no learning curve.

Studio bumped to 0.67.0; editor path-override pulls in 0.20.1
(flow-list row polish).

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

pubspec.lock

@@ -126,7 +126,7 @@ packages:
       path: "../fai_studio_flow_editor"
       relative: true
     source: path
-    version: "0.19.0"
+    version: "0.20.0"
   fake_async:
     dependency: transitive
     description: