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/kernel/src/keymap/keymap_service.dart

@@ -13,7 +13,7 @@
 ///
 /// Scope context is a `Map<String, bool>` keyed by named flags (e.g.
 /// `palette.open`, `editor.focused`). Producing services call
-/// [setScopeFlag] when their state changes; consumers reference the
+/// `setScopeFlag` when their state changes; consumers reference the
 /// flag name in when-clauses.
 library;