refactor: 文档维护点收归mipu-api，新增SDK

- 移除 docs/ 和 Release CI，文档维护点收归 mipu-api 子模块
- 新增 sdk/mipu_requests Python SDK（构造参数传入凭据）
- 新增 CLAUDE.md 标注文档维护路径
- 精简 README

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sdk/mipu_requests/exceptions.py

@@ -0,0 +1,33 @@
+"""mipu_requests 异常类 — 兼容 requests 异常命名"""
+
+
+class RequestException(Exception):
+    """基异常（对应 requests.exceptions.RequestException）"""
+    pass
+
+
+class APIError(RequestException):
+    """Bluebird API 返回非零 code"""
+
+    def __init__(self, response):
+        self.response = response
+        code = response.get("code", "?") if isinstance(response, dict) else "?"
+        msg = response.get("msg", "") if isinstance(response, dict) else str(response)
+        super().__init__(f"API error: code={code}, msg={msg}")
+
+
+class HTTPError(RequestException):
+    """目标网站返回 HTTP 错误状态码（对应 requests.exceptions.HTTPError）"""
+
+    def __init__(self, response):
+        self.response = response
+        super().__init__(f"{response.status_code} for {response.url}")
+
+
+class PollTimeoutError(RequestException):
+    """异步轮询超时"""
+
+    def __init__(self, agent_request_id, max_attempts=0):
+        self.agent_request_id = agent_request_id
+        self.max_attempts = max_attempts
+        super().__init__(f"Poll timeout after {max_attempts} attempts for {agent_request_id}")