fix(oidc): consent allow 改走 auth.x.ai form POST，修复 404

硬编码 Next-Action 在 accounts.x.ai consent 页轮换后返回
"Server action not found"。对齐当前 HTML form：POST
https://auth.x.ai/oauth2/authorize (action=allow)，旧
Next-Action 路径仅作 fallback。

oidc_mint/oauth_code.py

@@ -3,8 +3,14 @@
 对齐最新可用流程：authorize / consent 必须带 referrer=grok-build，
 否则 access_token JWT 缺少 referrer 字段，cli-chat-proxy / grok-build 不可用。
 
-参考实现：sso -> oauth2/authorize(referrer=grok-build) -> consent allow
+参考实现：sso -> oauth2/authorize(referrer=grok-build) -> consent page
+        -> POST auth.x.ai/oauth2/authorize (form action=allow)
         -> oauth2/token (authorization_code + PKCE)
+
+2026-07-16：accounts.x.ai consent 页 Next.js Server Action 频繁轮换，
+硬编码 Next-Action 会 404 "Server action not found"。
+官方 HTML form 的 action 指向 auth.x.ai/oauth2/authorize（非 consent URL），
+form-urlencoded + action=allow 可稳定拿到 code。
 """
 
 from __future__ import annotations
@@ -38,11 +44,11 @@ SCOPE = (
 )
 GROK_CLI_SCOPE = "grok-cli:access"
 GROK_REFERRER = "grok-build"
-# 对齐官方 stable CLI（2026-07-14：0.2.101）
+# 对齐官方 stable CLI（2026-07-14 二进制：0.2.101）
 GROK_VERSION = "0.2.101"
 GROK_TOKEN_UA = f"xai-grok-build/{GROK_VERSION}"
 GROK_CLIENT_SURFACE = "grok-build"
-# Next.js Server Action id（consent 页 POST 需要）
+# 旧 Next.js Server Action id（已失效，仅作 fallback 尝试）
 NEXT_ACTION_ID = "4005315a1d7e426de592990bb54bb37471f39dd6d2"
 BROWSER_UA = (
     "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
@@ -391,7 +397,85 @@ def parse_consent_code(body: str) -> str:
     raise OAuthCodeError(f"consent 响应缺少 code: {_short(text, 300)}")
 
 
-def approve_authorization(session: Any, consent_url: str, flow: AuthCodeFlow) -> str:
+def _code_from_location(url: str) -> str:
+    if not url or "code=" not in url:
+        return ""
+    qs = parse_qs(urlparse(url).query)
+    return str((qs.get("code") or [""])[0] or "").strip()
+
+
+def _approve_via_form_post(
+    session: Any, consent_url: str, flow: AuthCodeFlow
+) -> str:
+    """POST form to auth.x.ai/oauth2/authorize (matches consent page HTML)."""
+    redirect_uri = flow.redirect_uri or REDIRECT_URI_LEGACY
+    fields = {
+        "client_id": CLIENT_ID,
+        "redirect_uri": redirect_uri,
+        "scope": SCOPE,
+        "state": flow.state,
+        "code_challenge": flow.code_challenge,
+        "code_challenge_method": "S256",
+        "nonce": flow.nonce,
+        "principal_type": "User",
+        "principal_id": "",
+        "referrer": GROK_REFERRER,
+        "action": "allow",
+    }
+    headers = {
+        "User-Agent": BROWSER_UA,
+        "Accept": (
+            "text/html,application/xhtml+xml,application/xml;q=0.9,"
+            "*/*;q=0.8"
+        ),
+        "Content-Type": "application/x-www-form-urlencoded",
+        "Origin": "https://accounts.x.ai",
+        "Referer": consent_url,
+        "Sec-Fetch-Site": "same-site",
+        "Sec-Fetch-Mode": "navigate",
+        "Sec-Fetch-Dest": "document",
+        "Upgrade-Insecure-Requests": "1",
+        "Accept-Language": "en-US,en;q=0.9",
+    }
+    # 不自动 follow 到 127.0.0.1 loopback（本机无 listener）
+    resp = session.post(
+        AUTHORIZE_URL,
+        data=urlencode(fields),
+        headers=headers,
+        allow_redirects=False,
+        timeout=30,
+    )
+    loc = (
+        resp.headers.get("Location")
+        or resp.headers.get("location")
+        or ""
+    )
+    code = _code_from_location(loc)
+    if code:
+        return code
+
+    # 少数库会吞 Location 到 resp.url / 已 follow
+    final = _final_url(resp)
+    code = _code_from_location(final)
+    if code:
+        return code
+
+    text = resp.text or ""
+    if 200 <= resp.status_code < 300:
+        try:
+            return parse_consent_code(text)
+        except OAuthCodeError:
+            pass
+    raise OAuthCodeError(
+        f"consent form POST HTTP {resp.status_code}: "
+        f"loc={_short(loc, 120)} body={_short(text, 200)}"
+    )
+
+
+def _approve_via_next_action(
+    session: Any, consent_url: str, flow: AuthCodeFlow
+) -> str:
+    """旧路径：Next.js Server Action POST consent URL（action id 常失效）。"""
     redirect_uri = flow.redirect_uri or REDIRECT_URI_LEGACY
     payload = [
         {
@@ -413,24 +497,42 @@ def approve_authorization(session: Any, consent_url: str, flow: AuthCodeFlow) ->
         consent_url,
         data=body.encode("utf-8"),
         headers=_browser_headers("POST", consent_url, NEXT_ACTION_ID),
-        allow_redirects=True,
+        allow_redirects=False,
         timeout=30,
     )
     text = resp.text or ""
-    if resp.status_code < 200 or resp.status_code >= 300:
-        raise OAuthCodeError(f"consent HTTP {resp.status_code}: {_short(text, 300)}")
-
-    # 有时 302 到 redirect_uri?code=
-    final = _final_url(resp)
-    if "code=" in final:
-        qs = parse_qs(urlparse(final).query)
-        code = (qs.get("code") or [""])[0]
+    loc = (
+        resp.headers.get("Location")
+        or resp.headers.get("location")
+        or ""
+    )
+    code = _code_from_location(loc) or _code_from_location(_final_url(resp))
     if code:
         return code
-
+    if resp.status_code < 200 or resp.status_code >= 300:
+        raise OAuthCodeError(
+            f"consent Next-Action HTTP {resp.status_code}: {_short(text, 300)}"
+        )
     return parse_consent_code(text)
 
 
+def approve_authorization(session: Any, consent_url: str, flow: AuthCodeFlow) -> str:
+    """Approve consent and return authorization code.
+
+    优先：HTML form POST → https://auth.x.ai/oauth2/authorize
+    回退：旧 Next-Action POST consent URL（易 404）。
+    """
+    try:
+        return _approve_via_form_post(session, consent_url, flow)
+    except OAuthCodeError as form_exc:
+        try:
+            return _approve_via_next_action(session, consent_url, flow)
+        except OAuthCodeError as next_exc:
+            raise OAuthCodeError(
+                f"consent allow failed: form={form_exc}; next_action={next_exc}"
+            ) from next_exc
+
+
 def exchange_auth_code(session: Any, code: str, flow: AuthCodeFlow) -> TokenResult:
     redirect_uri = flow.redirect_uri or REDIRECT_URI_LEGACY
     form = {