[Developer] #204 Phase 1 MVP — Flutter app skeleton complete

- Drift 21 tables (8 catalog + 11 user + habit_dose_variants + meta_kv)
  with R1~R10 CHECK constraints and 19 indexes
- 8 hand-crafted seed JSON catalogs in app/assets/seed/
  (refs 84, protocols 34, methodologies 21, frame_patterns 30,
   reward_menu_items 30, break_protocols 8, common_frames 5, diet_patterns 5)
- 6 domain functions: recommend_variant, compute_streak,
  validate_frame_level, active_habit_quota, weekly_minimum_ratio,
  seed_importer (transactional, idempotent)
- 4 vertical-slice Riverpod screens: HabitList, HabitCreate, CheckIn, Streak
- 31 unit tests passing; flutter analyze clean
- OQ-5 streak semantics: missing entry ≠ explicit blank
  (missing = end of history; only TrackerValue.blank triggers Never-miss-twice)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/lib/ui/screens/habit_create_screen.dart

@@ -0,0 +1,137 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../../core/constants.dart';
+import '../../core/time.dart';
+import '../../data/db/daos/habit_dao.dart';
+import '../../domain/models/habit.dart';
+import '../../domain/rules/active_habit_quota.dart';
+import '../../state/providers.dart';
+
+class HabitCreateScreen extends ConsumerStatefulWidget {
+  const HabitCreateScreen({super.key});
+
+  @override
+  ConsumerState<HabitCreateScreen> createState() => _HabitCreateScreenState();
+}
+
+class _HabitCreateScreenState extends ConsumerState<HabitCreateScreen> {
+  final _formKey = GlobalKey<FormState>();
+  final _titleCtrl = TextEditingController();
+  final _framedCtrl = TextEditingController();
+  HabitType _type = HabitType.build;
+  FrameLevel _level = FrameLevel.l2;
+  bool _saving = false;
+
+  @override
+  void dispose() {
+    _titleCtrl.dispose();
+    _framedCtrl.dispose();
+    super.dispose();
+  }
+
+  Future<void> _save() async {
+    if (!_formKey.currentState!.validate()) return;
+    setState(() => _saving = true);
+    try {
+      final dao = ref.read(habitDaoProvider);
+      final count = await dao.countActive(
+        userId: kLocalDefaultUserId,
+        type: _type,
+      );
+      final quota = judgeActiveHabitQuota(type: _type, currentActiveCount: count);
+      if (!quota.allowed) {
+        if (!mounted) return;
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text(quota.reason)),
+        );
+        return;
+      }
+      await dao.insertWithVariants(HabitDraft(
+        userId: kLocalDefaultUserId,
+        type: _type,
+        title: _titleCtrl.text.trim(),
+        // Placeholder: vertical-slice uses the first seeded protocol.
+        protocolId: _type == HabitType.build ? 'morning_sunlight' : null,
+        breakProtocolId: _type == HabitType.breakHabit ? 'alcohol' : null,
+        frameLevel: _level,
+        frameFramedText: _framedCtrl.text.trim(),
+        startedAt: _ymd(nowKst()),
+      ));
+      if (!mounted) return;
+      Navigator.of(context).pop();
+    } catch (e) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text('저장 실패: $e')),
+      );
+    } finally {
+      if (mounted) setState(() => _saving = false);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('새 습관')),
+      body: Padding(
+        padding: const EdgeInsets.all(16),
+        child: Form(
+          key: _formKey,
+          child: ListView(
+            children: [
+              TextFormField(
+                controller: _titleCtrl,
+                decoration: const InputDecoration(labelText: '제목'),
+                validator: (v) =>
+                    (v == null || v.trim().isEmpty) ? '제목을 입력하세요' : null,
+              ),
+              const SizedBox(height: 16),
+              DropdownButtonFormField<HabitType>(
+                initialValue: _type,
+                items: const [
+                  DropdownMenuItem(value: HabitType.build, child: Text('만들기 (build)')),
+                  DropdownMenuItem(
+                      value: HabitType.breakHabit, child: Text('없애기 (break)')),
+                ],
+                onChanged: (v) => setState(() => _type = v ?? HabitType.build),
+                decoration: const InputDecoration(labelText: '타입'),
+              ),
+              const SizedBox(height: 16),
+              DropdownButtonFormField<FrameLevel>(
+                initialValue: _level,
+                items: const [
+                  DropdownMenuItem(value: FrameLevel.l2, child: Text('L2 · 조건부 긍정')),
+                  DropdownMenuItem(value: FrameLevel.l3, child: Text('L3 · 정체성')),
+                ],
+                onChanged: (v) => setState(() => _level = v ?? FrameLevel.l2),
+                decoration: const InputDecoration(labelText: '프레임 레벨'),
+              ),
+              const SizedBox(height: 16),
+              TextFormField(
+                controller: _framedCtrl,
+                decoration: const InputDecoration(
+                  labelText: '프레임 문구',
+                  hintText: '예: 아침 햇빛을 10분 받는다',
+                ),
+                maxLines: 2,
+                validator: (v) =>
+                    (v == null || v.trim().isEmpty) ? '프레임 문구를 입력하세요' : null,
+              ),
+              const SizedBox(height: 24),
+              FilledButton(
+                onPressed: _saving ? null : _save,
+                child: Text(_saving ? '저장 중...' : '저장'),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+String _ymd(DateTime d) =>
+    '${d.year.toString().padLeft(4, '0')}-'
+    '${d.month.toString().padLeft(2, '0')}-'
+    '${d.day.toString().padLeft(2, '0')}';