feat: 统一全链路时区为 UTC+8 (Asia/Shanghai)

- schema.sql created_at DEFAULT 改为 datetime(now,+8 hours)
- Dockerfile runtime 安装 tzdata ENV TZ=Asia/Shanghai 并软链 /etc/localtime
- docker-compose.yml 挂载宿主机 localtime 并传 TZ=Asia/Shanghai
- server index.ts 入口设置 process.env.TZ
- client utils/export 新增 utc8Now/utc8Input/utc8DateStamp/utc8DateTimeStamp
- Activities 默认活动开始/结束时间改用 UTC+8
- 导出文件名日期戳和报告生成时间统一 utc8DateStamp/utc8DateTimeStamp

server/src/db/schema.sql

@@ -27,7 +27,7 @@ CREATE TABLE IF NOT EXISTS activities (
   content TEXT,
   start_time TEXT NOT NULL,
   end_time TEXT NOT NULL,
-  created_at TEXT NOT NULL DEFAULT (datetime('now','localtime'))
+  created_at TEXT NOT NULL DEFAULT (datetime('now','+8 hours'))
 );
 
 CREATE TABLE IF NOT EXISTS activity_groups (
@@ -44,7 +44,7 @@ CREATE TABLE IF NOT EXISTS hours (
   user_id INTEGER NOT NULL,
   hours REAL NOT NULL DEFAULT 0,
   remark TEXT,
-  created_at TEXT NOT NULL DEFAULT (datetime('now','localtime')),
+  created_at TEXT NOT NULL DEFAULT (datetime('now','+8 hours')),
   FOREIGN KEY (activity_id) REFERENCES activities(id) ON DELETE CASCADE,
   FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
   UNIQUE(activity_id, user_id)
@@ -54,5 +54,5 @@ CREATE TABLE IF NOT EXISTS admins (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   username TEXT NOT NULL UNIQUE,
   password_hash TEXT NOT NULL,
-  created_at TEXT NOT NULL DEFAULT (datetime('now','localtime'))
+  created_at TEXT NOT NULL DEFAULT (datetime('now','+8 hours'))
 );