show pasted files/images as removable chips in the composer (T-142)

Pasting a file or image now adds a chip above the input instead of
inserting the raw @path as editable text: an image thumbnail
(Image.file of the cache/temp file, with an icon fallback) or a file
icon plus the basename, each with a × to cancel it before sending. On
submit the chips' @path tokens are appended to the typed text and the
chips clear.

resolveClipboardAttachment now returns ComposerAttachment descriptors
(path + isImage) rather than a pre-joined token string, so the composer
can render and manage each one. No new package dependency.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

test/builtin/claude/claude_composer_test.dart

@@ -4,6 +4,7 @@
 library;
 
 import 'package:clide/builtin/claude/src/claude_composer.dart';
+import 'package:clide/builtin/claude/src/clipboard_paste.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -80,7 +81,16 @@ void main() {
       expect(tester.widget<EditableText>(find.byType(EditableText)).readOnly, isTrue);
     });
 
-    testWidgets('Ctrl+V routes through the paste resolver and inserts its @path', (tester) async {
+    Future<void> pasteAttachment(WidgetTester tester) async {
+      tester.widget<EditableText>(find.byType(EditableText)).focusNode.requestFocus();
+      await tester.pump();
+      await tester.sendKeyDownEvent(LogicalKeyboardKey.control);
+      await tester.sendKeyEvent(LogicalKeyboardKey.keyV);
+      await tester.sendKeyUpEvent(LogicalKeyboardKey.control);
+      await tester.pumpAndSettle();
+    }
+
+    testWidgets('Ctrl+V of a file shows a chip and leaves the text field empty', (tester) async {
       // WidgetsApp provides DefaultTextEditingShortcuts in the real app;
       // the bare harness doesn't, so wrap explicitly to map Ctrl+V ->
       // PasteTextIntent, which the composer's Actions override intercepts.
@@ -89,22 +99,59 @@ void main() {
         DefaultTextEditingShortcuts(
           child: ClaudeComposer(
             onSubmit: (_) {},
-            pasteResolver: () async => '@/tmp/shot.png',
+            pasteResolver: () async => const [ComposerAttachment(path: '/tmp/notes.txt', isImage: false)],
           ),
         ),
       ));
-      tester.widget<EditableText>(find.byType(EditableText)).focusNode.requestFocus();
-      await tester.pump();
+      await pasteAttachment(tester);
 
-      await tester.sendKeyDownEvent(LogicalKeyboardKey.control);
-      await tester.sendKeyEvent(LogicalKeyboardKey.keyV);
-      await tester.sendKeyUpEvent(LogicalKeyboardKey.control);
+      expect(find.text('notes.txt'), findsOneWidget);
+      expect(tester.widget<EditableText>(find.byType(EditableText)).controller.text, isEmpty);
+    });
+
+    testWidgets('submit appends attachment @path tokens to the message', (tester) async {
+      final submitted = <String>[];
+      await tester.pumpWidget(harness(
+        f,
+        DefaultTextEditingShortcuts(
+          child: ClaudeComposer(
+            onSubmit: submitted.add,
+            pasteResolver: () async => const [ComposerAttachment(path: '/tmp/notes.txt', isImage: false)],
+          ),
+        ),
+      ));
+      await tester.enterText(find.byType(EditableText), 'look at this');
+      await pasteAttachment(tester);
+      await tester.sendKeyEvent(LogicalKeyboardKey.enter);
       await tester.pumpAndSettle();
 
-      expect(
-        tester.widget<EditableText>(find.byType(EditableText)).controller.text,
-        '@/tmp/shot.png',
-      );
+      expect(submitted, ['look at this @/tmp/notes.txt']);
+      // Chip cleared after send.
+      expect(find.text('notes.txt'), findsNothing);
+    });
+
+    testWidgets('remove × cancels the attachment before send', (tester) async {
+      final submitted = <String>[];
+      await tester.pumpWidget(harness(
+        f,
+        DefaultTextEditingShortcuts(
+          child: ClaudeComposer(
+            onSubmit: submitted.add,
+            pasteResolver: () async => const [ComposerAttachment(path: '/tmp/notes.txt', isImage: false)],
+          ),
+        ),
+      ));
+      await pasteAttachment(tester);
+      expect(find.text('notes.txt'), findsOneWidget);
+
+      await tester.tap(find.byKey(const ValueKey('composer-remove-/tmp/notes.txt')));
+      await tester.pumpAndSettle();
+      expect(find.text('notes.txt'), findsNothing);
+
+      await tester.enterText(find.byType(EditableText), 'just text');
+      await tester.sendKeyEvent(LogicalKeyboardKey.enter);
+      await tester.pumpAndSettle();
+      expect(submitted, ['just text']);
     });
   });
 }

test/builtin/claude/clipboard_paste_test.dart

@@ -25,13 +25,15 @@ void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
   group('resolveClipboardAttachment', () {
-    test('files become space-joined @path tokens (no temp file)', () async {
+    test('files become attachments with isImage by extension', () async {
       final source = _FakeSource(files: ['/home/u/a.txt', '/home/u/b.png']);
       final result = await resolveClipboardAttachment(source);
-      expect(result, '@/home/u/a.txt @/home/u/b.png');
+      expect(result.map((a) => a.path), ['/home/u/a.txt', '/home/u/b.png']);
+      expect(result.map((a) => a.isImage), [false, true]);
+      expect(result.map((a) => a.pathToken), ['@/home/u/a.txt', '@/home/u/b.png']);
     });
 
-    test('a raw image is written to a temp file and referenced by @path', () async {
+    test('a raw image is written to a temp file and attached', () async {
       final dir = await Directory.systemTemp.createTemp('clide-paste-test-');
       addTearDown(() => dir.delete(recursive: true));
       final bytes = Uint8List.fromList([0x89, 0x50, 0x4e, 0x47, 1, 2, 3]);
@@ -44,7 +46,9 @@ void main() {
       );
 
       final expectedPath = '${dir.path}/paste-1700000000000.png';
-      expect(result, '@$expectedPath');
+      expect(result, hasLength(1));
+      expect(result.single.isImage, isTrue);
+      expect(result.single.path, expectedPath);
       expect(await File(expectedPath).readAsBytes(), bytes);
     });
 
@@ -52,11 +56,18 @@ void main() {
       final result = await resolveClipboardAttachment(
         _FakeSource(files: ['/x/y'], image: Uint8List.fromList([1, 2])),
       );
-      expect(result, '@/x/y');
+      expect(result.map((a) => a.path), ['/x/y']);
     });
 
-    test('empty clipboard returns null (fall back to text)', () async {
-      expect(await resolveClipboardAttachment(_FakeSource()), isNull);
+    test('empty clipboard returns no attachments (fall back to text)', () async {
+      expect(await resolveClipboardAttachment(_FakeSource()), isEmpty);
+    });
+  });
+
+  group('ComposerAttachment', () {
+    test('fileName is the last path segment', () {
+      expect(const ComposerAttachment(path: '/a/b/c.png', isImage: true).fileName, 'c.png');
+      expect(const ComposerAttachment(path: 'bare.txt', isImage: false).fileName, 'bare.txt');
     });
   });