feat: keep the gateway's words on the OCR branches too

Issue #10 Task 4: the OCR side said only 'HTTP 404'. The issue reported
the chat path, but the batch that lost its 400 was reading tables - the
same blind spot, one transport over. Reuses the shared summarizer.

src/polygateway/transports/monkey_ocr.py

@@ -24,6 +24,11 @@ from polygateway.errors import (
     SourceDeadError,
     TransientError,
 )
+from polygateway.transports._http_errors import (
+    compose_message,
+    response_body,
+    summarize_body,
+)
 from polygateway.types import (
     OcrLayoutElement,
     OcrLayoutTransportResult,
@@ -74,13 +79,20 @@ def _translate_http_errors(source_name: str, operation: str) -> Iterator[None]:
 def _classify_status(
     exc: httpx.HTTPStatusError, source_name: str, operation: str
 ) -> TransientError | SourceDeadError | RequestRejectedError:
+    """HTTP 状态码 → 错误四分类,**全部分支**携带响应体摘要(issue #10)。
+
+    分类映射本身零变更;摘要口径与 chat 侧共用同一实现,不得在此另起一份——
+    "只有一个分支用了响应体"正是 issue #10 的成因。
+    """
     status = exc.response.status_code
+    summary = summarize_body(response_body(exc.response))
     ctx: dict[str, Any] = {
         "source_name": source_name,
         "status_code": status,
         "operation": operation,
+        "body_text": summary,
     }
-    message = f"{source_name} OCR {operation} HTTP {status}"
+    message = compose_message(f"{source_name} OCR {operation} HTTP {status}", summary)
     if status >= 500 or status == 429:
         return TransientError(message, **ctx)
     if status in (401, 403):