test: cover editor edit/save/close paths + SyntaxTextController

Follow-up to the multi-tab editor: extends the controller and view
tests to the close-tab, type-to-edit, and Ctrl+S-save paths, plus a
handful of controller edge branches (read errors, null-id events, the
suppressed self-echo, sibling-dirty marking). Adds a SyntaxTextController
suite driving a fake TreeSitterService so the span→TextSpan rendering
and byte→char mapping (including surrogate pairs) are exercised without
the native grammar. Restores total line coverage above the 95% floor.

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

test/builtin/editor/editor_view_test.dart

@@ -6,11 +6,16 @@ library;
 
 import 'package:clide/builtin/editor/src/editor_view.dart';
 import 'package:clide/clide.dart';
+import 'package:clide/widgets/widgets.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../../helpers/kernel_fixture.dart';
 import '../../helpers/widget_harness.dart';
 
+Finder _closeIcons() => find.byWidgetPredicate((w) => w is ClideIcon && w.painter is CloseIcon);
+
 IpcResponse _ok(Map<String, Object?> data) => IpcResponse.ok(id: '', data: data);
 
 Map<String, Object?> _buf(String id, String path, {bool dirty = false}) => {'id': id, 'path': path, 'dirty': dirty};
@@ -82,5 +87,59 @@ void main() {
 
       expect(activated, 'b_2');
     });
+
+    testWidgets('closing a tab routes to editor.close', (tester) async {
+      stubBuffers([_buf('b_1', 'lib/a.dart')], active: 'b_1');
+      String? closed;
+      f.ipc.stub('editor.close', (a) async {
+        closed = a['id'] as String?;
+        return _ok(const {});
+      });
+      await tester.pumpWidget(harness(f, const EditorView()));
+      await tester.pumpAndSettle();
+
+      expect(_closeIcons(), findsWidgets);
+      await tester.tap(_closeIcons().first);
+      await tester.pumpAndSettle();
+
+      expect(closed, 'b_1');
+    });
+
+    testWidgets('typing in the editor mirrors to editor.set-content', (tester) async {
+      stubBuffers([_buf('b_1', 'lib/a.dart')], active: 'b_1');
+      Map<String, Object?>? setArgs;
+      f.ipc.stub('editor.set-content', (a) async {
+        setArgs = a;
+        return _ok(const {});
+      });
+      await tester.pumpWidget(harness(f, const EditorView()));
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(EditableText), 'edited body');
+      await tester.pumpAndSettle();
+
+      expect(setArgs?['id'], 'b_1');
+      expect(setArgs?['text'], 'edited body');
+    });
+
+    testWidgets('Ctrl+S in the editor triggers editor.save', (tester) async {
+      stubBuffers([_buf('b_1', 'lib/a.dart')], active: 'b_1');
+      String? saved;
+      f.ipc.stub('editor.save', (a) async {
+        saved = a['id'] as String?;
+        return _ok(const {});
+      });
+      await tester.pumpWidget(harness(f, const EditorView()));
+      await tester.pumpAndSettle();
+
+      await tester.tap(find.byType(EditableText));
+      await tester.pump();
+      await tester.sendKeyDownEvent(LogicalKeyboardKey.controlLeft);
+      await tester.sendKeyEvent(LogicalKeyboardKey.keyS);
+      await tester.sendKeyUpEvent(LogicalKeyboardKey.controlLeft);
+      await tester.pumpAndSettle();
+
+      expect(saved, 'b_1');
+    });
   });
 }