refactor(i18n): route claude pane labels through the catalog (T-464)

Migrate the hardcoded user-facing strings across builtin.claude — composer,
conversation cards/segments, permission + AskUserQuestion prompts, task dock,
meta-sidebar (activity/config/team/roster), session/model pickers — to
ClideSettings.i18n.string/.interpolated, English kept as the placeholder;
builtin.claude_en_us.json extended to cover them. Context threaded into the
context-free render helpers (toolInputBody chain, _ConversationTurn) the same
way the mono family already is. No en_US behaviour change (D-21).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/builtin/claude/src/running_indicator.dart

@@ -87,7 +87,7 @@ class _RunningIndicatorState extends State<RunningIndicator> with SingleTickerPr
     final reduced = MediaQuery.maybeOf(context)?.disableAnimations ?? false;
     // The animated text is decorative; AT gets one stable label.
     return Semantics(
-      label: 'Claude is running',
+      label: ClideSettings.i18n.string(context, 'running.semantics', namespace: 'builtin.claude', placeholder: 'Claude is running'),
       child: ExcludeSemantics(
         child: reduced
             ? ClideText('${_verbs.first}…', color: claudeAccent, fontSize: clideFontMeta)