feat: vault-aligned server v1 + UX polish

Redesign the optional FastAPI companion around vault files (manifest /
PUT/GET/DELETE + OCR jobs) instead of legacy strokes_json notes. Wire a
client Server settings panel for health/login. Polish shell UX: l10n for
settings/home/board, sticky-board empty state, and a narrow-screen
diagnostics FAB.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/l10n/app_localizations_en.dart

@@ -489,4 +489,103 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get syncNotConfigured => 'Enter a server URL to enable sync.';
+
+  @override
+  String get settingsDefaults => 'Defaults';
+
+  @override
+  String get settingsAppearance => 'Appearance';
+
+  @override
+  String get settingsAbout => 'About';
+
+  @override
+  String get settingsDefaultTool => 'Default tool';
+
+  @override
+  String get settingsDefaultColor => 'Default color';
+
+  @override
+  String get settingsDefaultWidth => 'Default stroke width';
+
+  @override
+  String get settingsPressureCurve => 'Pressure curve';
+
+  @override
+  String get settingsClearConfirmBody =>
+      'This resets pen defaults and appearance. Notes and documents are not affected.';
+
+  @override
+  String get serverSection => 'BadNote Server';
+
+  @override
+  String get serverUrl => 'Server URL';
+
+  @override
+  String get serverUrlHint => 'http://192.168.1.10:8080';
+
+  @override
+  String get serverUsername => 'Username';
+
+  @override
+  String get serverPassword => 'Password';
+
+  @override
+  String get serverSave => 'Save & sign in';
+
+  @override
+  String get serverTest => 'Test connection';
+
+  @override
+  String serverTestOk(String version) {
+    return 'Connected · API $version';
+  }
+
+  @override
+  String serverTestFail(String error) {
+    return 'Connection failed: $error';
+  }
+
+  @override
+  String get serverLoggedIn => 'Signed in';
+
+  @override
+  String get serverHint =>
+      'Optional. Self-hosted vault assist + deferred OCR; notes stay fully offline.';
+
+  @override
+  String get boardEmptyTitle => 'No sticky notes yet';
+
+  @override
+  String get boardEmptyBody =>
+      'Tap + to add a card. Write [[other-card-id]] in the body to create a backlink.';
+
+  @override
+  String get relativeJustNow => 'Just now';
+
+  @override
+  String relativeMinutesAgo(int n) {
+    return '${n}m ago';
+  }
+
+  @override
+  String relativeHoursAgo(int n) {
+    return '${n}h ago';
+  }
+
+  @override
+  String get relativeYesterday => 'Yesterday';
+
+  @override
+  String diagExported(int bytes) {
+    return 'Diagnostic pack exported ($bytes bytes)\nPath copied';
+  }
+
+  @override
+  String diagExportFail(String error) {
+    return 'Export failed: $error';
+  }
+
+  @override
+  String get processingOcr => 'Processing OCR…';
 }