feat: integrate Authelia SSO and update LLDAP routing

dashboard/backend/routers/auth.py

@@ -109,6 +109,30 @@ async def login(creds: LoginRequest, request: Request):
         "has_2fa": bool(totp_secret)
     }
 
+@router.get("/proxy")
+async def proxy_auth(request: Request):
+    """Auto-login when Authelia has already authenticated the user via forward-auth.
+    Caddy sets Remote-User header after successful Authelia 2FA verification."""
+    remote_user = request.headers.get("Remote-User")
+    if not remote_user:
+        raise HTTPException(status_code=401, detail="No proxy auth header")
+    # Map the LDAP user to the dashboard admin user
+    # Only allow known users (the admin)
+    if remote_user != config.ADMIN_USER:
+        raise HTTPException(status_code=403, detail="User not authorized for dashboard")
+    access_token = auth.create_access_token(
+        data={"sub": remote_user},
+        expires_delta=timedelta(minutes=config.ACCESS_TOKEN_EXPIRE_MINUTES),
+    )
+    refresh_token = auth.create_refresh_token(data={"sub": remote_user})
+    return {
+        "access_token": access_token,
+        "refresh_token": refresh_token,
+        "token_type": "bearer",
+        "user": remote_user,
+        "has_2fa": True,
+    }
+
 @router.get("/me")
 async def read_users_me(current_user: str = Depends(auth.get_current_user)):
     totp_secret = auth.load_totp_secret()