feat(app): reviews know how a card was studied; progress can start afresh

Each review records its mode (ADR 0004, rule 3): front to back, back to
front with a schedule of its own, or crammed outside the schedule. A
card's schedule replays only the reviews of one mode. Resetting progress
appends a 'reset' entry per card, no migration (the column is text):
schedules replay what follows it, and the history stays for the streak
and the heatmap. Reviews are inserted in batches.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/test/support/fake_review_gateway.dart

@@ -14,19 +14,17 @@ class FakeReviewGateway() implements ReviewGateway {
   ];
 
   @override
-  Future<void> insert({
-    required String cardId,
-    required int rating,
-    required DateTime reviewedAt,
-    required int durationMs,
-  }) async {
-    rows.add((
-      id: 'review-${(_nextId++).toString().padLeft(4, '0')}',
-      cardId: cardId,
-      rating: rating,
-      reviewedAt: reviewedAt,
-      durationMs: durationMs,
-    ));
+  Future<void> insert(Iterable<ReviewRow> reviews) async {
+    for (final review in reviews) {
+      rows.add((
+        id: 'review-${(_nextId++).toString().padLeft(4, '0')}',
+        cardId: review.cardId,
+        rating: review.rating,
+        reviewedAt: review.reviewedAt,
+        durationMs: review.durationMs,
+        mode: review.mode,
+      ));
+    }
   }
 
   @override