feat: 企业微信OAuth静默登录

- 新增 GET /api/wecom/oauth-url 和 /api/wecom/oauth-callback
- OAuth回调返回HTML页面直接写localStorage（避坑企微webview 307重定向不可靠）
- 菜单URL改为OAuth静默授权链接（snsapi_base + agentid）
- redirect目标编码到state参数中（避坑redirect_uri不允许自定义query）
- wecom_userid大小写不敏感匹配
- 前端路由守卫处理 ?token= 自动登录（fallback）
- Login.vue企微环境检测自动跳OAuth
- setup-menu同步更新为OAuth链接

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

backend/app/api/wecom.py

@@ -7,7 +7,7 @@ from typing import Optional
 from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
 from defusedxml import ElementTree as ET
 from fastapi import APIRouter, Depends, HTTPException, Query, Request
-from fastapi.responses import PlainTextResponse
+from fastapi.responses import PlainTextResponse, HTMLResponse
 from pydantic import BaseModel
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
@@ -248,12 +248,13 @@ async def test_message(
 @router.post("/setup-menu")
 async def setup_menu(current_user: dict = Depends(require_director)):
     """Create the standard app menu (开始填报 view + 绑定账号 click)."""
+    oauth_url = _build_oauth_url()
     buttons = [
-        {"type": "view", "name": "开始填报", "url": "https://qj.dhdx.fun/m"},
+        {"type": "view", "name": "开始填报", "url": oauth_url},
         {"type": "click", "name": "绑定账号", "key": "BIND_ACCOUNT"},
     ]
     success = await wecom_client.create_menu(buttons)
-    return {"success": success, "message": "菜单已部署 (view + click)" if success else "菜单创建失败"}
+    return {"success": success, "message": "菜单已部署 (含静默登录)" if success else "菜单创建失败"}
 
 
 @router.get("/menu")
@@ -271,3 +272,90 @@ async def trigger_daily_check(
     """Manually trigger the daily reporting check (for testing or manual use)."""
     result = await check_daily_reporting(db)
     return result
+
+
+# ── OAuth silent login ──
+
+import urllib.parse
+from app.services.auth import build_token_for_user
+
+
+def _build_oauth_url(redirect_path: str = "/m") -> str:
+    """Build the WeChat Work OAuth2 authorize URL (snsapi_base = silent).
+    The redirect target is encoded in the 'state' param to avoid query-string issues
+    with the OAuth redirect_uri validation."""
+    if not settings.WECOM_CORP_ID:
+        return f"https://qj.dhdx.fun{redirect_path}"
+    params = urllib.parse.urlencode({
+        "appid": settings.WECOM_CORP_ID,
+        "redirect_uri": "https://qj.dhdx.fun/api/wecom/oauth-callback",
+        "response_type": "code",
+        "scope": "snsapi_base",
+        "agentid": settings.WECOM_AGENT_ID,
+        "state": f"r={urllib.parse.quote(redirect_path)}",
+    })
+    return f"https://open.weixin.qq.com/connect/oauth2/authorize?{params}#wechat_redirect"
+
+
+@router.get("/oauth-url")
+async def get_oauth_url(redirect: str = Query("/m")):
+    """Redirect to the WeChat Work OAuth authorize URL (silent login)."""
+    from fastapi.responses import RedirectResponse
+    return RedirectResponse(url=_build_oauth_url(redirect))
+
+
+@router.get("/oauth-callback")
+async def oauth_callback(
+    code: str = Query(...),
+    state: str = Query(""),
+    db: AsyncSession = Depends(get_db),
+):
+    """WeChat Work OAuth2 callback — exchange code for userid, find bound user, auto-login."""
+    # Parse redirect target from state param: "r=%2Fm"
+    redirect = "/m"
+    if state.startswith("r="):
+        redirect = urllib.parse.unquote(state[2:])
+
+    # Exchange code for wecom userinfo
+    userinfo = await wecom_client.get_userinfo_by_code(code)
+    if not userinfo:
+        raise HTTPException(status_code=400, detail="Failed to exchange code with WeChat Work")
+
+    wecom_userid = userinfo.get("UserId") or userinfo.get("userid")
+    if not wecom_userid:
+        raise HTTPException(status_code=400, detail="Could not get userid from WeChat Work")
+
+    # Find bound user (case-insensitive — WeChat Work userids may vary in case)
+    from sqlalchemy import func as sa_func
+    result = await db.execute(
+        select(User).where(sa_func.lower(User.wecom_userid) == wecom_userid.lower())
+    )
+    user = result.scalar_one_or_none()
+    if not user:
+        # Not bound — redirect to bind page
+        bind_url = f"https://qj.dhdx.fun/wecom-bind?wecom_userid={wecom_userid}"
+        from fastapi.responses import RedirectResponse
+        return RedirectResponse(url=bind_url)
+
+    # Issue JWT and auto-login via HTML page — saves credentials to localStorage, then redirects
+    token = build_token_for_user(user)
+    import json as _json
+    auth_data = _json.dumps({
+        "token": token,
+        "userId": str(user.id),
+        "userName": user.name,
+        "userRole": user.role,
+        "theme": user.theme or "editorial",
+    }, ensure_ascii=False)
+    frontend_url = f"https://qj.dhdx.fun{redirect}"
+    html = f"""<!DOCTYPE html><html><head><meta charset="utf-8"><title>登录中...</title></head>
+<body><script>
+var d = {auth_data};
+localStorage.setItem('token', d.token);
+localStorage.setItem('userId', d.userId);
+localStorage.setItem('userName', d.userName);
+localStorage.setItem('userRole', d.userRole);
+localStorage.setItem('theme', d.theme);
+window.location.replace({_json.dumps(frontend_url)});
+</script></body></html>"""
+    return HTMLResponse(content=html, status_code=200)