[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/domain/frame/validate_frame_level.dart

@@ -0,0 +1,150 @@
+import '../models/frame_pattern.dart';
+import '../models/habit.dart';
+
+enum FrameValidationStatus { accept, warn, reject }
+
+class FrameInput {
+  final FrameLevel level;
+  final String? originalText;
+  final String framedText;
+  const FrameInput({
+    required this.level,
+    required this.framedText,
+    this.originalText,
+  });
+}
+
+class AvoidanceHit {
+  final String keyword;
+  final int startIndex;
+  final int endIndex;
+  final FramePatternModel source;
+  const AvoidanceHit({
+    required this.keyword,
+    required this.startIndex,
+    required this.endIndex,
+    required this.source,
+  });
+}
+
+class FrameSuggestion {
+  final FrameLevel level;
+  final String text;
+  final FramePatternModel source;
+  const FrameSuggestion({
+    required this.level,
+    required this.text,
+    required this.source,
+  });
+}
+
+class FrameValidationResult {
+  final FrameValidationStatus status;
+  final List<AvoidanceHit> avoidanceHits;
+  final List<FrameSuggestion> suggestions;
+  const FrameValidationResult({
+    required this.status,
+    this.avoidanceHits = const [],
+    this.suggestions = const [],
+  });
+}
+
+/// fn-validate-frame-level: R3 (L0/L1 reject) + R7 (avoidance keywords).
+FrameValidationResult validateFrameLevel(
+  FrameInput input, {
+  required Iterable<FramePatternModel> knownPatterns,
+}) {
+  if (input.framedText.isEmpty) {
+    return const FrameValidationResult(
+      status: FrameValidationStatus.reject,
+    );
+  }
+
+  if (input.level == FrameLevel.l0 || input.level == FrameLevel.l1) {
+    final suggestions = _buildSuggestions(input.framedText, knownPatterns);
+    return FrameValidationResult(
+      status: FrameValidationStatus.reject,
+      suggestions: suggestions,
+    );
+  }
+
+  final hits = detectAvoidanceKeywords(input.framedText, knownPatterns);
+  if (hits.isEmpty) {
+    return const FrameValidationResult(status: FrameValidationStatus.accept);
+  }
+
+  final suggestions = _buildSuggestionsFromHits(hits);
+  return FrameValidationResult(
+    status: FrameValidationStatus.warn,
+    avoidanceHits: hits,
+    suggestions: suggestions,
+  );
+}
+
+List<AvoidanceHit> detectAvoidanceKeywords(
+  String text,
+  Iterable<FramePatternModel> patterns,
+) {
+  final hits = <AvoidanceHit>[];
+  final seen = <String>{};
+  for (final p in patterns) {
+    var idx = text.indexOf(p.avoidanceKeyword);
+    while (idx >= 0) {
+      final key = '$idx:${p.avoidanceKeyword}';
+      if (!seen.contains(key)) {
+        seen.add(key);
+        hits.add(AvoidanceHit(
+          keyword: p.avoidanceKeyword,
+          startIndex: idx,
+          endIndex: idx + p.avoidanceKeyword.length,
+          source: p,
+        ));
+      }
+      idx = text.indexOf(p.avoidanceKeyword, idx + 1);
+    }
+  }
+  return hits;
+}
+
+List<FrameSuggestion> _buildSuggestions(
+  String text,
+  Iterable<FramePatternModel> patterns,
+) {
+  final relevant = patterns
+      .where((p) => text.contains(p.avoidanceKeyword))
+      .toList();
+  // If no keyword matches (L0 with no detectable avoidance), suggest from
+  // 'general' domain.
+  final pool = relevant.isEmpty
+      ? patterns.where((p) => p.domain == 'general').toList()
+      : relevant;
+  return _expandSuggestions(pool);
+}
+
+List<FrameSuggestion> _buildSuggestionsFromHits(List<AvoidanceHit> hits) {
+  final unique = <String, FramePatternModel>{};
+  for (final h in hits) {
+    unique[h.source.id] = h.source;
+  }
+  return _expandSuggestions(unique.values.toList());
+}
+
+List<FrameSuggestion> _expandSuggestions(List<FramePatternModel> sources) {
+  final out = <FrameSuggestion>[];
+  for (final p in sources) {
+    out.add(FrameSuggestion(
+      level: FrameLevel.l2,
+      text: p.l2Suggestion,
+      source: p,
+    ));
+    if (p.l3Identity != null) {
+      out.add(FrameSuggestion(
+        level: FrameLevel.l3,
+        text: p.l3Identity!,
+        source: p,
+      ));
+    }
+    if (out.length >= 5) break;
+  }
+  return out.take(5).toList();
+}