[03-Developer] #260 round 2: AC-9 + AC-10 보강

QA round 1 환송 노트 (#260 카테고리 63 환송) 의 두 결함 수정.

AC-9 — tool result 2KB 가드 runtime 연결
- chat_providers.dart userTurn: result.toJson() → encodeToolResult 통과
  후 jsonDecode 한 Map 을 LlmChatSession.sendToolResult 로 전달.
- encodeToolResult 가 더 이상 dead code 가 아니다. ADR-0005 / OQ-2
  의 2KB hard cap 이 실 경로에서 적용됨.
- 회귀: chat_session_controller_test.dart 신규 'AC-9 대용량 → cap'
  케이스 — 인위 huge_dump tool 로 _truncated:true + _hint 검증.

AC-10 — widget E2E 신규
- app/test/ui/chat_screen_test.dart 신규 (2 testWidgets):
  1) add_habit tool call → ConfirmDialog '수행' → habits +1 + 모델 마무리.
  2) ConfirmDialog '취소' → habits 무변화 + 'tool 취소됨' 라벨.
- ProviderScope overrides: appDatabaseProvider / llmServiceProvider /
  bootstrapProvider / toolDepsProvider.

회귀
- 신규 3 (cap 1 + widget 2) → 151 → 154 passed (1 skip)
- flutter analyze: clean

Refs #260

app/lib/state/chat_providers.dart

@@ -1,3 +1,5 @@
+import 'dart:convert';
+
 import 'package:flutter/widgets.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
@@ -183,7 +185,12 @@ class ChatSessionController extends StateNotifier<ChatSessionState> {
         );
 
         pendingToolName = toolCall.name;
-        pendingToolResult = result.toJson();
+        // ADR-0005 / OQ-2: hard-cap tool result at 2KB so LLM context window
+        // can't be blown by a runaway ToolOk payload. encodeToolResult applies
+        // truncate-with-hint when needed; jsonDecode round-trips back to a Map
+        // because the chat session API expects Map<String, dynamic>.
+        final capped = jsonDecode(encodeToolResult(result)) as Map<String, dynamic>;
+        pendingToolResult = capped;
         final capturedName = pendingToolName;
         final capturedResult = pendingToolResult;
         nextStream = () => _session!.sendToolResult(

app/test/state/chat_session_controller_test.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:life_helper/ai/tools/tool_definition.dart';
 import 'package:life_helper/ai/tools/tool_dispatcher.dart';
 import 'package:life_helper/ai/tools/tool_envelope.dart';
 import 'package:life_helper/ai/tools/tool_registry.dart';
@@ -163,6 +164,46 @@ void main() {
     expect(h.controller.state.error, isNull);
   });
 
+  testWidgets('대용량 tool result → 2KB cap 적용 (AC-9)', (tester) async {
+    // 인위적으로 큰 payload 를 돌려주는 fake tool 로 dispatcher 를 구성.
+    final hugePayload = {
+      'items': List.generate(200, (i) => {'id': 'p_$i' * 5, 'text': 'x' * 20}),
+    };
+    final hugeTool = ToolDefinition(
+      name: 'huge_dump',
+      description: 'test-only huge result',
+      parametersSchema: const {
+        'type': 'object',
+        'properties': {},
+        'required': [],
+      },
+      handler: (_, _) async => ToolOk(hugePayload),
+    );
+    final ctx2 = await bootstrapToolDeps();
+    addTearDown(() => ctx2.db.close());
+    final mock = MockLlmService();
+    await mock.load();
+    final controller = ChatSessionController(
+      llm: mock,
+      dispatcher: ToolDispatcher(registry: ToolRegistry([hugeTool])),
+      deps: ctx2.deps,
+      tools: [hugeTool],
+    );
+    addTearDown(controller.dispose);
+    final ctx = await mountContext(tester);
+
+    mock.enqueueChatEvents([const LlmFunctionCall('huge_dump', {})]);
+    mock.enqueueChatEvents([const LlmTextChunk('처리 완료.')]);
+
+    await controller.userTurn('덤프', ctx);
+
+    final submitted = mock.lastChat!.toolResults.first.$2;
+    expect(submitted['status'], 'ok');
+    // encodeToolResult 가 cap 적용 → _truncated 마커 + _hint 메시지 포함.
+    expect((submitted['data'] as Map)['_truncated'], true);
+    expect((submitted['data'] as Map)['_hint'], contains('query_protocol'));
+  });
+
   testWidgets('tool result 가 다음 sendToolResult 로 전달', (tester) async {
     final h = await makeHarness();
     addTearDown(() {

app/test/ui/chat_screen_test.dart

@@ -0,0 +1,130 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:life_helper/data/ai/llm_service.dart';
+import 'package:life_helper/state/ai_providers.dart';
+import 'package:life_helper/state/chat_providers.dart';
+import 'package:life_helper/state/providers.dart';
+import 'package:life_helper/ui/screens/chat_screen.dart';
+
+import '../ai/tools/_tool_test_helpers.dart';
+
+/// Widget E2E for #260 (AC-10). Verifies the full chat → tool call →
+/// ConfirmDialog → habit DB insert pipeline using a fully wired
+/// ChatSessionController, with a `MockLlmService` standing in for Gemma.
+void main() {
+  testWidgets(
+    'add_habit tool call → ConfirmDialog 수행 → 활성 습관 +1',
+    (tester) async {
+      final ctx = await bootstrapToolDeps();
+      addTearDown(() => ctx.db.close());
+
+      final mock = MockLlmService();
+      await mock.load();
+      // Turn 1 (sendUser): LLM 이 add_habit 호출.
+      mock.enqueueChatEvents([
+        const LlmFunctionCall('add_habit', {
+          'protocol_id': 'morning_sunlight',
+          'frame_level': 'L2',
+          'framed_text': '아침에 햇빛 보기',
+        }),
+      ]);
+      // Turn 2 (sendToolResult): LLM 이 자연어로 마무리.
+      mock.enqueueChatEvents([
+        const LlmTextChunk('아침 햇빛 습관을 추가했어요.'),
+      ]);
+
+      await tester.pumpWidget(
+        ProviderScope(
+          overrides: [
+            appDatabaseProvider.overrideWithValue(ctx.db),
+            llmServiceProvider.overrideWithValue(mock),
+            // bootstrapProvider 는 이미 ctx 에서 SeedImporter 가 끝났으므로 no-op.
+            bootstrapProvider.overrideWith((ref) async {}),
+            // toolDepsProvider 를 미리 resolve 된 형태로 주입.
+            toolDepsProvider.overrideWith((ref) async => ctx.deps),
+          ],
+          child: const MaterialApp(home: ChatScreen()),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      // 활성 습관 0개에서 시작.
+      var habits =
+          await ctx.deps.habitDao.activeHabitsForUser(ctx.deps.userId);
+      expect(habits, isEmpty);
+
+      // 사용자 입력 → 전송.
+      await tester.enterText(find.byType(TextField), '아침 햇빛 추가해줘');
+      await tester.tap(find.byIcon(Icons.send));
+      await tester.pump(); // userTurn 시작
+      await tester.pump(const Duration(milliseconds: 50)); // mock stream
+
+      // ConfirmDialog 가 떠야 한다.
+      expect(find.text('이 작업을 수행할까요?'), findsOneWidget);
+      expect(find.text('수행'), findsOneWidget);
+      expect(find.text('취소'), findsOneWidget);
+
+      // 수행 탭.
+      await tester.tap(find.text('수행'));
+      await tester.pumpAndSettle();
+
+      // 활성 습관 1개.
+      habits = await ctx.deps.habitDao.activeHabitsForUser(ctx.deps.userId);
+      expect(habits, hasLength(1));
+      expect(habits.first.frameFramedText, '아침에 햇빛 보기');
+
+      // UI 에 모델 마무리 문구도 보인다.
+      expect(find.text('아침 햇빛 습관을 추가했어요.'), findsOneWidget);
+    },
+  );
+
+  testWidgets(
+    'ConfirmDialog 취소 → habit DB 변화 없음, ToolCancelled 메시지',
+    (tester) async {
+      final ctx = await bootstrapToolDeps();
+      addTearDown(() => ctx.db.close());
+
+      final mock = MockLlmService();
+      await mock.load();
+      mock.enqueueChatEvents([
+        const LlmFunctionCall('add_habit', {
+          'protocol_id': 'morning_sunlight',
+          'frame_level': 'L2',
+          'framed_text': '아침에 햇빛 보기',
+        }),
+      ]);
+      mock.enqueueChatEvents([
+        const LlmTextChunk('알겠어요, 추가하지 않았어요.'),
+      ]);
+
+      await tester.pumpWidget(
+        ProviderScope(
+          overrides: [
+            appDatabaseProvider.overrideWithValue(ctx.db),
+            llmServiceProvider.overrideWithValue(mock),
+            bootstrapProvider.overrideWith((ref) async {}),
+            toolDepsProvider.overrideWith((ref) async => ctx.deps),
+          ],
+          child: const MaterialApp(home: ChatScreen()),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), '추가');
+      await tester.tap(find.byIcon(Icons.send));
+      await tester.pump();
+      await tester.pump(const Duration(milliseconds: 50));
+
+      expect(find.text('이 작업을 수행할까요?'), findsOneWidget);
+      await tester.tap(find.text('취소'));
+      await tester.pumpAndSettle();
+
+      final habits =
+          await ctx.deps.habitDao.activeHabitsForUser(ctx.deps.userId);
+      expect(habits, isEmpty);
+      // tool call 메시지 라벨이 '취소됨' 으로 표시.
+      expect(find.textContaining('취소됨'), findsOneWidget);
+    },
+  );
+}