feat: add WebDAV sync support and startup/shutdown scripts

Backend:
- Add uuid, sync_version, is_deleted fields to all syncable models
- Add SyncSettings model for WebDAV configuration (AES-256-GCM encrypted passwords)
- Add crypto.py: AES-256-GCM encryption derived from JWT_SECRET via PBKDF2
- Add sync_lock.py: thread-level sync lock with 503 middleware for write blocking
- Add webdav.py: WebDAV client using requests (PUT/GET/MKCOL/DELETE)
- Add sync_service.py: push/pull/bidirectional merge with LWW conflict resolution
- Add sync router with 8 endpoints: config, test, push, pull, sync, status, remote delete
- Add UUID backfill for existing records in init_db()
- Add SQLAlchemy before_update event to auto-increment sync_version
- Register sync middleware to block writes during sync (503)

Frontend:
- Add sync API client (WebUI/src/api/sync.ts)
- Add useSyncStore with config, test, push/pull/sync operations
- Add WebDAV config + sync UI in SettingsView
- Add 503 status code handling in axios interceptor
- Add uuid field to all TypeScript type definitions

Scripts:
- Add scripts/start.bat and scripts/stop.bat for project management

Design doc: docs/plan/webdav-sync-design.md

api/app/database.py

@@ -1,23 +1,18 @@
-from sqlalchemy import create_engine, inspect, text, String, Integer, Text, Boolean, Float, DateTime, Date
-from sqlalchemy.ext.declarative import declarative_base
-from sqlalchemy.orm import sessionmaker
-import os
+from sqlalchemy import create_engine, inspect, text, String, Integer, Text, Boolean, Float, DateTime, Date, event
+from sqlalchemy.orm import declarative_base, sessionmaker
 
-from app.config import DATABASE_PATH, DATABASE_URL
+from app.config import DATABASE_URL
 
-# 确保 data 目录存在
-os.makedirs(os.path.dirname(DATABASE_PATH) if os.path.dirname(DATABASE_PATH) else ".", exist_ok=True)
-
-# 创建引擎
 engine = create_engine(
     DATABASE_URL,
-    connect_args={"check_same_thread": False}
+    pool_size=10,
+    max_overflow=20,
+    pool_recycle=3600,
+    pool_pre_ping=True,
 )
 
-# 创建会话工厂
 SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
 
-# 创建基类
 Base = declarative_base()
 
 
@@ -30,20 +25,18 @@ def get_db():
         db.close()
 
 
-# SQLAlchemy 类型到 SQLite 类型名的映射
 _TYPE_MAP = {
     String: "VARCHAR",
     Integer: "INTEGER",
     Text: "TEXT",
     Boolean: "BOOLEAN",
-    Float: "REAL",
-    DateTime: "DATETIME",
+    Float: "DOUBLE PRECISION",
+    DateTime: "TIMESTAMP",
     Date: "DATE",
 }
 
 
 def _col_type_str(col_type) -> str:
-    """将 SQLAlchemy 列类型转为 SQLite 类型字符串"""
     if col_type.__class__ in _TYPE_MAP:
         base = _TYPE_MAP[col_type.__class__]
     else:
@@ -56,14 +49,13 @@ def _col_type_str(col_type) -> str:
 
 
 def init_db():
-    """初始化数据库表，自动补充新增的列"""
-    # 导入所有模型，确保 Base.metadata 包含全部表定义
+    """初始化数据库表，自动补充新增的列，并为缺少 uuid 的记录回填"""
+    from app.utils.logger import logger  # 避免循环导入
     from app.models import (  # noqa: F401
-        task, category, tag, user_settings, habit, anniversary, goal,
+        task, category, tag, user_settings, habit, anniversary, goal, sync_settings,
     )
     Base.metadata.create_all(bind=engine)
 
-    # 通用自动迁移：对比 ORM 模型与实际表结构，补充缺失的列（SQLite 兼容）
     inspector = inspect(engine)
     table_names = set(inspector.get_table_names())
 
@@ -78,24 +70,75 @@ def init_db():
             for col in table_cls.columns:
                 if col.name in existing_cols:
                     continue
-                # 跳过无服务端默认值且不可为空的列（容易出错）
                 if col.nullable is False and col.server_default is None and col.default is None:
                     continue
 
-                sqlite_type = _col_type_str(col.type)
+                col_type_str = _col_type_str(col.type)
+                col_name = col.name
 
-                ddl = f"ALTER TABLE {table_name} ADD COLUMN {col.name} {sqlite_type}"
-
-                # 为可空列或已有默认值的列附加 DEFAULT
                 if col.server_default is not None:
+                    ddl = f"ALTER TABLE {table_name} ADD COLUMN {col_name} {col_type_str}"
                     ddl += f" DEFAULT {col.server_default.arg}"
-                elif col.default is not None and col.nullable:
+                    if not col.nullable:
+                        ddl += " NOT NULL"
+                elif col.default is not None:
                     default_val = col.default.arg
-                    if isinstance(default_val, str):
+                    ddl = f"ALTER TABLE {table_name} ADD COLUMN {col_name} {col_type_str}"
+                    if isinstance(default_val, bool):
+                        ddl += f" DEFAULT {'TRUE' if default_val else 'FALSE'}"
+                    elif isinstance(default_val, str):
                         ddl += f" DEFAULT '{default_val}'"
-                    elif isinstance(default_val, bool):
-                        ddl += f" DEFAULT {1 if default_val else 0}"
                     else:
                         ddl += f" DEFAULT {default_val}"
+                    if not col.nullable:
+                        ddl += " NOT NULL"
+                else:
+                    ddl = f"ALTER TABLE {table_name} ADD COLUMN {col_name} {col_type_str}"
 
                 conn.execute(text(ddl))
+
+    # 为缺少 uuid 的已有记录回填 UUID4
+    import uuid
+    db_session = SessionLocal()
+    try:
+        from app.models import Task, Category, Tag, HabitGroup, Habit, HabitCheckin
+        from app.models import AnniversaryCategory, Anniversary, Goal, GoalStep, GoalReview, SyncSettings
+
+        for model_cls in [Task, Category, Tag, HabitGroup, Habit, HabitCheckin,
+                         AnniversaryCategory, Anniversary, Goal, GoalStep, GoalReview]:
+            if hasattr(model_cls, 'uuid'):
+                null_uuid_records = db_session.query(model_cls).filter(
+                    (model_cls.uuid == None) | (model_cls.uuid == '')  # noqa: E711
+                ).all()
+                for record in null_uuid_records:
+                    record.uuid = str(uuid.uuid4())
+                if null_uuid_records:
+                    logger.info(f"为 {len(null_uuid_records)} 条 {model_cls.__name__} 记录回填了 uuid")
+        db_session.commit()
+    except Exception as e:
+        logger.warning(f"UUID 回填时出现异常（可忽略）: {e}")
+        db_session.rollback()
+    finally:
+        db_session.close()
+
+    # 注册 sync_version 自增事件监听
+    _register_sync_version_listeners()
+
+
+def _bump_sync_version(mapper, connection, target):
+    """before_update 事件：自动递增 sync_version（同步模式中跳过）"""
+    from app.utils.sync_lock import is_sync_mode
+    if not is_sync_mode() and hasattr(target, 'sync_version'):
+        target.sync_version = (target.sync_version or 0) + 1
+
+
+def _register_sync_version_listeners():
+    """为所有可同步模型注册 before_update 事件监听"""
+    from app.models import (
+        Task, Category, Tag, HabitGroup, Habit, HabitCheckin,
+        AnniversaryCategory, Anniversary, Goal, GoalStep, GoalReview,
+    )
+    for model_cls in [Task, Category, Tag, HabitGroup, Habit, HabitCheckin,
+                      AnniversaryCategory, Anniversary, Goal, GoalStep, GoalReview]:
+        if hasattr(model_cls, 'sync_version'):
+            event.listen(model_cls, 'before_update', _bump_sync_version)