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/widgets/src/clide_icon_test.dart

@@ -0,0 +1,33 @@
+import 'package:clide/widgets/widgets.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../helpers/kernel_fixture.dart';
+import '../../helpers/widget_harness.dart';
+
+void main() {
+  group('ClideIcon', () {
+    late KernelFixture f;
+    setUp(() async => f = await KernelFixture.create());
+    tearDown(() async => f.dispose());
+
+    testWidgets('sizes a SizedBox + CustomPaint to the given size',
+        (tester) async {
+      await tester.pumpWidget(
+        harness(f, const ClideIcon(FolderIcon(), size: 24)),
+      );
+      final sb = tester.widget<SizedBox>(find.byType(SizedBox).first);
+      expect(sb.width, 24);
+      expect(sb.height, 24);
+      expect(find.byType(CustomPaint), findsWidgets);
+    });
+
+    testWidgets('default color is globalForeground', (tester) async {
+      await tester.pumpWidget(
+        harness(f, const ClideIcon(CheckIcon())),
+      );
+      // Color is inaccessible after painting; ensure it renders without crashing.
+      expect(find.byType(ClideIcon), findsOneWidget);
+    });
+  });
+}