feat: 周期账单 — 自动生成定期交易（房租/订阅/工资）

server/src/db/init.ts

@@ -243,6 +243,40 @@ async function runMigrations(conn: mysql.Connection) {
       ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
     `)
   }
+
+  // 周期账单模板表
+  const hasRecurring = await tableExists(conn, 'recurring_templates')
+  if (!hasRecurring) {
+    console.log('[DB] Migrating: creating recurring_templates table')
+    await conn.query(`
+      CREATE TABLE IF NOT EXISTS recurring_templates (
+        id INT AUTO_INCREMENT PRIMARY KEY,
+        user_id INT NOT NULL,
+        amount INT NOT NULL COMMENT '单位：分',
+        type ENUM('expense', 'income') NOT NULL,
+        category_id INT NOT NULL,
+        note VARCHAR(200) DEFAULT '',
+        frequency ENUM('weekly', 'monthly', 'yearly') NOT NULL DEFAULT 'monthly',
+        next_date DATE NOT NULL COMMENT '下次生成日期',
+        end_date DATE DEFAULT NULL COMMENT '截止日期，NULL=永久',
+        is_active TINYINT(1) DEFAULT 1,
+        group_id INT DEFAULT NULL,
+        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+        updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+        INDEX idx_user (user_id),
+        INDEX idx_next_date (next_date),
+        FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
+        FOREIGN KEY (category_id) REFERENCES categories(id) ON DELETE CASCADE
+      ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
+    `)
+  }
+
+  // transactions 表添加 recurring_id
+  const hasRecurringId = await columnExists(conn, 'transactions', 'recurring_id')
+  if (!hasRecurringId) {
+    console.log('[DB] Migrating: adding recurring_id to transactions')
+    await conn.query("ALTER TABLE transactions ADD COLUMN recurring_id INT DEFAULT NULL COMMENT '关联的周期模板ID' AFTER group_id")
+  }
 }
 
 export async function initDatabase() {