工作台重命名：无界·无界 → 学会·无界

- ALL_TENANTS / session / seed / migrations 全部同步
- 新增 migrate_rename_tenant() 数据迁移，启动自动 UPDATE 所有表
- migrations/ 模式重构（参考 SalesManager）

backend/migrations/seed.py

@@ -0,0 +1,55 @@
+"""migrations/seed.py — 初始化默认用户和示例数据（仅在空库时执行）"""
+
+from datetime import date
+
+
+def migrate_seed_users():
+    """初始化默认用户和工作台权限（仅空库时执行）"""
+    from flask_app import db, _exec, one, generate_password_hash
+
+    conn = db()
+    try:
+        if one(conn, "SELECT id FROM users LIMIT 1"):
+            return  # 已有用户，跳过
+
+        default_users = [
+            ("qiukai", "yxcowork2026", "qiukai", "admin"),
+            ("kepu", "kepu123", "科普负责人", "opc_owner"),
+            ("keyan", "keyan123", "科研负责人", "opc_owner"),
+            ("yihuan", "yihuan123", "医患负责人", "opc_owner"),
+            ("mcn", "mcn123", "MCN负责人", "opc_owner"),
+            ("wuji", "wuji123", "无界负责人", "opc_owner"),
+        ]
+        for username, pwd, display, role in default_users:
+            _exec(conn, "INSERT INTO users (username, password_hash, display_name, role, created_at) VALUES (?,?,?,?,?)",
+                  (username, generate_password_hash(pwd, "pbkdf2:sha256"), display, role, date.today().isoformat()))
+
+        # 绑定工作台
+        tenant_map = [
+            ("kepu", "科普·无界"), ("keyan", "科研·无界"), ("yihuan", "医患·无界"),
+            ("mcn", "MCN·无界"), ("wuji", "学会·无界"),
+        ]
+        for uname, tenant in tenant_map:
+            u = one(conn, "SELECT id FROM users WHERE username=?", (uname,))
+            if u:
+                _exec(conn, "INSERT INTO user_tenants (user_id, tenant) VALUES (?,?)", (u["id"], tenant))
+
+        conn.commit()
+        print("[migrate] 默认用户已初始化")
+    finally:
+        conn.close()
+
+
+def migrate_seed_demo_data():
+    """填充初始示例数据（仅在空库时执行）"""
+    from flask_app import db, one, seed_db
+
+    conn = db()
+    try:
+        if one(conn, "SELECT id FROM sales_leads LIMIT 1"):
+            return  # 已有数据，跳过
+    finally:
+        conn.close()
+
+    seed_db()
+    print("[migrate] 示例数据已填充")