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/conversation_card.dart

@@ -270,7 +270,9 @@ class _ConversationCardState extends State<ConversationCard> {
   }
 
   Widget _caret(SurfaceTokens tokens) {
-    final label = _collapsed ? 'Expand' : 'Collapse';
+    final label = _collapsed
+        ? ClideSettings.i18n.string(context, 'card.expand', namespace: 'builtin.claude', placeholder: 'Expand')
+        : ClideSettings.i18n.string(context, 'card.collapse', namespace: 'builtin.claude', placeholder: 'Collapse');
     return Semantics(
       button: true,
       label: label,
@@ -298,11 +300,11 @@ class _ConversationCardState extends State<ConversationCard> {
       case ConversationCardStatus.success:
         icon = const CheckIcon();
         color = tokens.statusSuccess;
-        label = 'succeeded';
+        label = ClideSettings.i18n.string(context, 'card.succeeded', namespace: 'builtin.claude', placeholder: 'succeeded');
       case ConversationCardStatus.error:
         icon = const CloseIcon();
         color = tokens.statusError;
-        label = 'failed';
+        label = ClideSettings.i18n.string(context, 'card.failed', namespace: 'builtin.claude', placeholder: 'failed');
       case ConversationCardStatus.none:
         return const SizedBox.shrink();
     }
@@ -331,7 +333,9 @@ class _ConversationCardState extends State<ConversationCard> {
 
   List<Widget> _actions(SurfaceTokens tokens) {
     final items = <_ActionItem>[];
-    if (widget.copyText != null) items.add(_ActionItem('copy', _copy));
+    if (widget.copyText != null) {
+      items.add(_ActionItem(ClideSettings.i18n.string(context, 'card.copy', namespace: 'builtin.claude', placeholder: 'copy'), _copy));
+    }
     for (final a in widget.actions) {
       items.add(_ActionItem(a.label, a.onInvoke));
     }