Add spell practice, memory analytics, auth persistence, and word library UX.

Includes per-word training stats and curves, quiz session auto-save, remember-login,
paginated word list with floating page arrows, and Obsidian-style relationship graph baseline.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/scripts/seed_user_words.py

@@ -0,0 +1,143 @@
+"""向用户词库批量导入单词（测试用）。
+
+用法（backend 目录）:
+  python -m scripts.seed_user_words --username john --count 200
+  python -m scripts.seed_user_words --username john --count 200 --with-quiz 80
+"""
+
+from __future__ import annotations
+
+import argparse
+import random
+import sys
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+
+BACKEND_DIR = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(BACKEND_DIR))
+
+from database import SessionLocal  # noqa: E402
+from models import DictionaryEntry, QuizRecord, User, Word  # noqa: E402
+from services.word_service import calc_mastery_score, utc_now_iso  # noqa: E402
+
+
+def utc_now_iso_at(dt: datetime) -> str:
+    return dt.strftime("%Y-%m-%dT%H:%M:%SZ")
+
+
+def seed_words(
+    db,
+    user: User,
+    count: int,
+    offset: int,
+) -> tuple[int, int]:
+    existing_pairs = {
+        (w.source_text, w.target_text)
+        for w in db.query(Word).filter(Word.user_id == user.id).all()
+    }
+    entries = (
+        db.query(DictionaryEntry)
+        .order_by(DictionaryEntry.id)
+        .offset(offset)
+        .limit(count * 3)
+        .all()
+    )
+    added = 0
+    skipped = 0
+    now = utc_now_iso()
+
+    for e in entries:
+        if added >= count:
+            break
+        zh = (e.zh or "").strip()
+        en = (e.lemma_en or "").strip().lower()
+        if not zh or not en:
+            skipped += 1
+            continue
+        if (en, zh) in existing_pairs or (zh, en) in existing_pairs:
+            skipped += 1
+            continue
+
+        word = Word(
+            user_id=user.id,
+            source_text=zh,
+            target_text=en,
+            source_lang="zh",
+            target_lang="en",
+            phonetic=e.phonetic,
+            example_en=e.example_en,
+            example_cn=e.example_cn,
+            status=random.choice(["new", "new", "learning", "mastered", "weak"]),
+            correct_count=random.randint(0, 8),
+            wrong_count=random.randint(0, 4),
+            consecutive_correct_count=random.randint(0, 3),
+            mastery_score=0,
+            train_count=0,
+            total_train_seconds=0,
+            review_due_date=datetime.now(timezone.utc).strftime("%Y-%m-%d"),
+            created_at=now,
+        )
+        word.mastery_score = calc_mastery_score(word.correct_count, word.wrong_count)
+        db.add(word)
+        existing_pairs.add((zh, en))
+        added += 1
+
+    db.commit()
+    return added, skipped
+
+
+def seed_quiz_records(db, user: User, max_records: int) -> int:
+    words = db.query(Word).filter(Word.user_id == user.id).all()
+    if not words:
+        return 0
+    now = datetime.now(timezone.utc)
+    created = 0
+    for i in range(max_records):
+        w = random.choice(words)
+        is_correct = random.random() > 0.35
+        t = now - timedelta(days=random.randint(0, 20), hours=random.randint(0, 23))
+        record = QuizRecord(
+            user_id=user.id,
+            word_id=w.id,
+            question_type=random.choice(["en_to_zh", "zh_to_en", "spell"]),
+            user_answer="test",
+            correct_answer="test",
+            is_correct=1 if is_correct else 0,
+            duration_seconds=random.randint(3, 45),
+            created_at=utc_now_iso_at(t),
+        )
+        db.add(record)
+        created += 1
+    db.commit()
+    return created
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="批量导入用户单词")
+    parser.add_argument("--username", default="john")
+    parser.add_argument("--count", type=int, default=200)
+    parser.add_argument("--offset", type=int, default=5000, help="词典偏移，避免总取相同词")
+    parser.add_argument("--with-quiz", type=int, default=0, help="额外生成 N 条模拟训练记录")
+    args = parser.parse_args()
+
+    db = SessionLocal()
+    try:
+        user = db.query(User).filter(User.username == args.username).first()
+        if not user:
+            print(f"用户不存在: {args.username}", file=sys.stderr)
+            sys.exit(1)
+
+        before = db.query(Word).filter(Word.user_id == user.id).count()
+        added, skipped = seed_words(db, user, args.count, args.offset)
+        after = db.query(Word).filter(Word.user_id == user.id).count()
+        print(f"用户 {args.username}: 原有 {before} 词, 新增 {added}, 跳过 {skipped}, 现有 {after} 词")
+
+        if args.with_quiz > 0:
+            n = seed_quiz_records(db, user, args.with_quiz)
+            print(f"已生成模拟训练记录 {n} 条")
+    finally:
+        db.close()
+
+
+if __name__ == "__main__":
+    main()