docs: fix 41 unresolved dartdoc references

Convert non-resolving [refs] in doc comments to backtick code-spans across 24
lib/ files (param/field names out of doc scope, method refs on other classes,
non-API strings like regex char-classes and command ids). Verified 0
"unresolved doc reference" warnings via `dart doc --validate-links`. The
dart-doc CI gate (test.yml) never ran before — Gitea Actions was inactive — so
this debt had accumulated unchecked.

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

lib/builtin/claude/src/conversation_controller.dart

@@ -28,8 +28,8 @@ class ConversationController extends ChangeNotifier {
   }
 
   /// Build a controller fed from the kernel [MessageBus] — it consumes
-  /// the [ConversationItem]s a [TranscriptPublisher] writes onto
-  /// [publisher]/[channel]. Decouples the view from the reader so several
+  /// the [ConversationItem]s a `TranscriptPublisher` writes onto
+  /// `publisher`/[channel]. Decouples the view from the reader so several
   /// panels can render the same conversation (team work, T-139/T-140).
   factory ConversationController.fromBus({required MessageBus messages, String channel = ClaudeConversation.leadChannel, Future<void> Function()? onDispose}) {
     final stream = messages