feat(vim): ex command-line overlay (:w :q :wq :x :e :N, ZZ) (T-407)

Under the Vim preset, `:` opens a transient one-line ex overlay running a
fixed v1 table; ZZ runs :wq directly. Completes the last built child of the
T-403 cross-pane vim layer (T-405 part 2 gt/gT still open).

- ExLineController + parseExCommand grammar + editor-targeted executors
  (lib/kernel/src/ex_line.dart); the overlay (lib/widgets/src/ex_line_overlay
  .dart) reuses the quick-open chrome, mounts in the root_shell Stack, and
  publishes the exline.open scope flag. Unknown commands flash + stay open;
  with no active buffer every command no-ops (2026-06-13 decision).
- :q closes the active tab via editor.close on its id — the registry promotes
  the next buffer and the split self-collapses on the last (2026-06-12
  decision); :w/:wq/:x/ZZ save (+close) the active buffer.
- :e <path> seeds quick-open (new QuickOpenController.open(seed:)); :N adds the
  editor.goto-line IPC/CLI verb (reuses _offsetForLine). Goto needs caret sync:
  EditorController now handles editor.selection-changed and the editor view
  moves the caret on a selection-only change.
- `:` and ZZ are typed intents; the editor matcher and PaneKeyNav now bubble
  unhandled typed intents to the app-root Actions, so they fire from any focus.
  vim.yaml binds `:`, ZZ (shift+z shift+z), and Esc-dismiss.

Tests: parser/controller/executors, editor.goto-line daemon tests,
selection-changed (controller + view), full overlay widget test. make test
green; analyze + format clean.

Also files T-441 (drop bold from the ticket-id card label) and T-442
(sub-agent renders as 3 cards instead of one bundle) under the T-276 UI epic.

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

lib/kernel/src/facade.dart

@@ -26,6 +26,7 @@ import 'package:clide/kernel/src/notify.dart';
 import 'package:clide/kernel/src/os.dart';
 import 'package:clide/kernel/src/panels/arrangement.dart';
 import 'package:clide/kernel/src/panels/registry.dart';
+import 'package:clide/kernel/src/ex_line.dart';
 import 'package:clide/kernel/src/project.dart';
 import 'package:clide/kernel/src/quick_open.dart';
 import 'package:clide/kernel/src/reader_nav.dart';
@@ -58,6 +59,7 @@ class KernelServices {
     required this.commands,
     required this.palette,
     required this.quickOpen,
+    required this.exLine,
     required this.recentFiles,
     required this.readerNav,
     required this.keybindings,
@@ -97,6 +99,9 @@ class KernelServices {
   final CommandRegistry commands;
   final PaletteController palette;
   final QuickOpenController quickOpen;
+
+  /// Transient Vim ex command-line overlay state (T-407).
+  final ExLineController exLine;
   final RecentFilesService recentFiles;
   final ReaderNavRegistry readerNav;
   final KeybindingResolver keybindings;
@@ -167,6 +172,7 @@ class KernelServices {
     final palette = PaletteController(commands);
     final recentFiles = RecentFilesService();
     final quickOpen = QuickOpenController(recentPaths: () => recentFiles.paths);
+    final exLine = ExLineController();
     final readerNav = ReaderNavRegistry(messages);
     final clipboard = ClideClipboard();
     final files = FileServices(events);
@@ -253,6 +259,7 @@ class KernelServices {
       commands: commands,
       palette: palette,
       quickOpen: quickOpen,
+      exLine: exLine,
       recentFiles: recentFiles,
       readerNav: readerNav,
       keybindings: keybindings,
@@ -286,6 +293,7 @@ class KernelServices {
     commands.dispose();
     palette.dispose();
     quickOpen.dispose();
+    exLine.dispose();
     toast.dispose();
     recentFiles.dispose();
     readerNav.dispose();