read user-scope Claude config files via a read allow-list (D-80)

The reader opened repo-local .claude markdown but rejected user-scope
files under ~/.claude with "path outside workspace" — that dir is
global, outside the repo, and files.read was repo-confined (T-102).

Per D-76 the Claude config surface is clide-managed, so files.read now
resolves a path under an allow-list: the workspace root plus trusted
extra read roots (FilesService.extraReadRoots), wired in main.dart to
~/.claude when present. Reads widen; writes stay repo-confined, and the
symlink re-check still refuses a config-root symlink that escapes. Off-
root paths and `..` traversal are rejected as before.

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

lib/main.dart

@@ -166,7 +166,17 @@ Future<void> main() async {
     final eventSink = _BusEventSink(events);
     final paneRegistry = PaneRegistry(events: eventSink);
     registerPaneCommands(dispatcher, paneRegistry);
-    final filesService = FilesService(root: workRoot, events: eventSink);
+    // Trusted read-only roots beyond the workspace: the global Claude
+    // config dir (~/.claude), so the reader can open user-scope skill /
+    // agent / command markdown the Config tab surfaces (D-80, T-195).
+    // The repo-local .claude is already under workRoot.
+    final extraReadRoots = <Directory>[];
+    final claudeHome = Platform.environment['HOME'];
+    if (claudeHome != null) {
+      final globalClaude = Directory('$claudeHome/.claude');
+      if (globalClaude.existsSync()) extraReadRoots.add(globalClaude);
+    }
+    final filesService = FilesService(root: workRoot, events: eventSink, extraReadRoots: extraReadRoots);
     registerFilesCommands(dispatcher, filesService);
     // Search reuses the files service's resolved ignore set so the
     // grep honours the same ignore_files: layering (D-4 / D-79).