fix: auth_proxy Cache-Control no-cache + POST redirect fallback

- Login page now sends Cache-Control: no-cache (prevent browser caching)
- POST /login falls back to query string redirect param
- Gitea redirect issue was caused by cached old login page without redirect field

auth_proxy/auth_proxy.py

@@ -154,6 +154,7 @@ class AuthHandler(http.server.BaseHTTPRequestHandler):
             html = html.replace('ERROR_PLACEHOLDER', '')
         self.send_response(200)
         self.send_header('Content-Type', 'text/html; charset=utf-8')
+        self.send_header('Cache-Control', 'no-cache, no-store, must-revalidate')
         self.send_header('Content-Length', str(len(html.encode())))
         self.end_headers()
         self.wfile.write(html.encode())
@@ -203,8 +204,9 @@ class AuthHandler(http.server.BaseHTTPRequestHandler):
             form = urllib.parse.parse_qs(body)
             username = form.get('username', [''])[0]
             password = form.get('password', [''])[0]
-            redirect = form.get('redirect', ['https://nav.xybkwd.top/'])[0]
-
+            qs_params = urllib.parse.parse_qs(parsed.query)
+            qs_redirect = qs_params.get('redirect', ['https://nav.xybkwd.top/'])[0]
+            redirect = form.get('redirect', [qs_redirect])[0]
             if username == 'fxy' and bcrypt.checkpw(password.encode(), PASSWORD_HASH):
                 token = make_token(username)
                 # Domain=.xybkwd.top for cross-subdomain cookie sharing