add app test suite — unit, widget, golden, a11y (168 tests)

Four layers under app/test/:

  * kernel/, extension/ — unit tests for every kernel service and
    the extension contract. i18n fallback chain gets the full
    matrix (exact/lang/default/placeholder, namespace isolation,
    unknown namespace, interpolation). Theme resolver and
    extension-manager topo sort covered.
  * widgets/, builtin/ — widget tests for every primitive and each
    Tier 0 built-in. Assertions reach into the Semantics node so
    a missing label fails structurally, not visually.
  * goldens/ — Alchemist + Ahem font for cross-platform pixel
    stability; primitives only (button, tab bar, icon set). No
    goldens for compositions — they'd churn through every tier.
  * a11y/ — contract-level gate: semantic coverage walks the
    built-in catalogue, contrast walks every token pair in every
    bundled theme against WCAG-AA thresholds (catches real
    regressions: the first run caught `tab.inactive_text` at 2.81
    in summer-night), i18n coverage asserts every referenced key
    exists in its catalog (exists-in-map, not "key == value" — too
    ambiguous for keys that happen to equal their translation).

Helpers under helpers/: `KernelFixture.create()` boots a
KernelServices with in-memory stores + a FakeDaemonClient (no
socket, drivable connected-state), `widget_harness` wraps a
widget in the minimum tree that resolves theme + i18n.

Co-Authored-By: Claude <noreply@anthropic.com>

app/test/kernel/src/commands/registry_test.dart

@@ -0,0 +1,51 @@
+import 'package:clide/clide.dart';
+import 'package:clide_app/extension/extension.dart';
+import 'package:clide_app/kernel/kernel.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+CommandContribution _cmd(String name, Future<IpcResponse> Function() run) =>
+    CommandContribution(
+      id: name,
+      command: name,
+      title: 'cmd $name',
+      run: (_) => run(),
+    );
+
+void main() {
+  group('CommandRegistry', () {
+    test('register exposes the command; all enumerates', () {
+      final r = CommandRegistry();
+      r.register(_cmd('a', () async => IpcResponse.ok(id: '', data: const {})));
+      r.register(_cmd('b', () async => IpcResponse.ok(id: '', data: const {})));
+      expect(r.all.map((c) => c.command).toList(), ['a', 'b']);
+      expect(r.get('a'), isNotNull);
+    });
+
+    test('execute returns the handler response', () async {
+      final r = CommandRegistry();
+      r.register(
+        _cmd(
+          'ping',
+          () async => IpcResponse.ok(id: '', data: const {'pong': true}),
+        ),
+      );
+      final resp = await r.execute('ping');
+      expect(resp.ok, true);
+      expect(resp.data['pong'], true);
+    });
+
+    test('execute on unknown returns NotFound error', () async {
+      final r = CommandRegistry();
+      final resp = await r.execute('missing');
+      expect(resp.ok, false);
+      expect(resp.error!.code, IpcExitCode.notFound);
+    });
+
+    test('unregister removes the command', () {
+      final r = CommandRegistry();
+      r.register(_cmd('x', () async => IpcResponse.ok(id: '', data: const {})));
+      r.unregister('x');
+      expect(r.get('x'), isNull);
+    });
+  });
+}