feat(auth): 平台成唯一账号源——小程序微信登录进 users + OPC 报名资料字段

统一用户账号体系（阶段1，非破坏）：
- UserRepository 新增 get_by_wx_mini_openid。
- /auth/wx-login：小程序登录(X-Client=miniprogram)按 wx_mini_openid 建/复用
  users 账号(role=opc_member, source=mini_program, auth_type=wx_openid)，
  并带 nickName/avatarUrl；非小程序仍走 wx_openid。
- /auth/me + 登录响应补齐小程序契约字段 name/phone/phoneBound。
- users 增 opc_status/topics 列(alembic 0010)；desktop/web profile 也输出
  name/phone/phoneBound/status/topics，且 update-profile 支持 name/status/topics 映射。
- scripts/db/seed.py 增 accounts→users 幂等迁移：旧小程序账号并入全局 users
  (wx_mini_openid/phone 关联 + opc_member 身份)，由用户执行 migrate+seed。

Co-Authored-By: Claude <noreply@anthropic.com>

scripts/db/seed.py

@@ -47,6 +47,52 @@ def _seed_training() -> None:
         conn.close()
 
 
+async def _migrate_accounts_to_users(db) -> None:
+    """把培训端 accounts 存量并入平台 users（幂等：已存在账号跳过并保证身份）。
+
+    迁移旧小程序账号 → users（wx_mini_openid/phone 关联），使微信/手机登录仍命中，
+    且并入全局唯一账号体系。迁移/种子由用户执行（铁律），禁止运行态调用。
+    """
+    import secrets
+    import sqlite3
+    from app.training import db as tdb
+    from app.api.routers.auth import _ensure_opc_identity
+
+    conn = sqlite3.connect(tdb.DB_PATH)
+    conn.row_factory = sqlite3.Row
+    migrated = created = 0
+    try:
+        for row in conn.execute("SELECT * FROM accounts"):
+            username = (row["username"] or "").strip()
+            wxid = (row["wxid"] or "").strip()
+            phone = (row["phone"] or "").strip()
+            if not username and not wxid and not phone:
+                continue
+            user = (await db.users.get_by_username(username)) if username else None
+            if user is None and phone:
+                user = await db.users.get_by_username(phone)
+            if user is None and wxid:
+                user = (await db.users.get_by_wx_mini_openid(wxid)
+                        or await db.users.get_by_wx_openid(wxid))
+            if user is None:
+                uname = (username or phone or f"wx_{wxid[:24]}")
+                user = await db.users.create(
+                    username=uname, password=secrets.token_hex(16),
+                    nickname=(row["name"] or uname), avatar=(row["avatar"] or ""),
+                    phone=phone, wx_mini_openid=wxid or "",
+                    wx_openid=(f"wx_{wxid[:24]}" if wxid else ""),
+                    source="mini_program",
+                    auth_type=("wx_openid" if wxid else ("phone" if phone else "unknown")),
+                    role="opc_member",
+                )
+                created += 1
+            await _ensure_opc_identity(db, user["id"])
+            migrated += 1
+        log.info("accounts→users 迁移完成：共 %s 条，新建 %s 条", migrated, created)
+    finally:
+        conn.close()
+
+
 async def run() -> None:
     db = Database()
     try:
@@ -54,6 +100,7 @@ async def run() -> None:
         await db.session.commit()
         log.info("平台种子完成：%s", config.DATABASE_URL)
         _seed_training()
+        await _migrate_accounts_to_users(db)
     except Exception as e:  # noqa: BLE001
         await db.session.rollback()
         log.error("种子失败：%s", e)