dissolve app/ into repo root (D-056)

Single Flutter package at the repo root. All code, tests, assets,
and platform directories moved from app/ to root. Package renamed
from clide_app to clide — all imports rewritten. Merged pubspec
combines core (ffi) and app (flutter, yaml, xterm) dependencies.
Makefile simplified: no APP_PRESENT conditionals, no cd, no daemon
lifecycle. 317 tests pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

test/kernel/src/events/bus_test.dart

@@ -0,0 +1,69 @@
+import 'package:clide/kernel/kernel.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('EventBus', () {
+    late EventBus bus;
+
+    setUp(() => bus = EventBus());
+    tearDown(() => bus.dispose());
+
+    test('emit delivers to stream subscribers', () async {
+      final events = <ClideEventEnvelope>[];
+      final sub = bus.stream.listen(events.add);
+      bus.emit(const ThemeChanged(themeName: 'summer-night'));
+      await Future<void>.delayed(Duration.zero);
+      expect(events, hasLength(1));
+      expect(events.first.event, isA<ThemeChanged>());
+      await sub.cancel();
+    });
+
+    test('on<T>() filters by runtime type', () async {
+      final themes = <ThemeChanged>[];
+      final extensions = <ExtensionActivated>[];
+      final s1 = bus.on<ThemeChanged>().listen(themes.add);
+      final s2 = bus.on<ExtensionActivated>().listen(extensions.add);
+      bus.emit(const ThemeChanged(themeName: 'a'));
+      bus.emit(const ExtensionActivated(id: 'builtin.git'));
+      bus.emit(const ThemeChanged(themeName: 'b'));
+      await Future<void>.delayed(Duration.zero);
+      expect(themes.map((e) => e.themeName), ['a', 'b']);
+      expect(extensions.map((e) => e.id), ['builtin.git']);
+      await s1.cancel();
+      await s2.cancel();
+    });
+
+    test('broadcasts to multiple listeners independently', () async {
+      final a = <ClideEvent>[];
+      final b = <ClideEvent>[];
+      final s1 = bus.stream.listen((e) => a.add(e.event));
+      final s2 = bus.stream.listen((e) => b.add(e.event));
+      bus.emit(const ThemeChanged(themeName: 'x'));
+      await Future<void>.delayed(Duration.zero);
+      expect(a, hasLength(1));
+      expect(b, hasLength(1));
+      await s1.cancel();
+      await s2.cancel();
+    });
+
+    test('emit after dispose is a silent no-op', () async {
+      await bus.dispose();
+      // must not throw
+      bus.emit(const ThemeChanged(themeName: 'nope'));
+    });
+
+    test('envelope stamps a timestamp', () async {
+      final capture = <ClideEventEnvelope>[];
+      final sub = bus.stream.listen(capture.add);
+      final before = DateTime.now().toUtc();
+      bus.emit(const ThemeChanged(themeName: 'n'));
+      await Future<void>.delayed(Duration.zero);
+      final after = DateTime.now().toUtc();
+      expect(capture, hasLength(1));
+      final ts = capture.first.timestamp;
+      expect(ts.isAfter(before) || ts.isAtSameMomentAs(before), isTrue);
+      expect(ts.isBefore(after) || ts.isAtSameMomentAs(after), isTrue);
+      await sub.cancel();
+    });
+  });
+}