Fallback SSO OAuth mint to browser PKCE when Python TLS fails.

HTTP mint often dies on auth.x.ai (curl OpenSSL / SSLEOFError); reuse the
registration browser to set SSO, complete authorize+consent, and fetch tokens
so CPA export/push to cpa.nopj.cn can continue.

grok_register_ttk.py

@@ -85,6 +85,7 @@ DEFAULT_CONFIG = {
     # OIDC：优先 SSO→Authorization Code + referrer=grok-build
     "cpa_prefer_sso_oauth": True,        # True=用 sso cookie 走 PKCE（必须带 referrer）
     "cpa_require_referrer": True,        # True=access_token 无 referrer=grok-build 则失败
+    "cpa_allow_browser_fallback": True,  # True=HTTP 铸造失败时用注册浏览器走 PKCE（绕 Python TLS）
     "cpa_allow_device_fallback": False,  # True=SSO 失败时回退设备码（通常不可用）
     # OIDC 铸造代理/超时
     "mint_proxy": "",                    # 铸造专用代理；空=复用 proxy