fix(jina): log transient failures at WARNING without traceback (#2484) (#2485)

The exception handler in JinaClient.crawl used logger.exception, which
emits an ERROR-level record with the full httpx/httpcore/anyio traceback
for every transient network failure (timeout, connection refused). Other
search/crawl providers in the project log the same class of recoverable
failures as a single line. One offline/slow-network session could produce
dozens of multi-frame ERROR stack traces, drowning out real problems.

Switch to logger.warning with a concise message that includes the
exception type and its str, matching the style used elsewhere for
recoverable transient failures (aio_sandbox, ddg, etc.). The exception
type now also surfaces into the returned "Error: ..." string so callers
retain diagnostic signal.

Adds a regression test that asserts the log record is WARNING, carries
no exc_info, and includes the exception class name.

Co-authored-by: voidborne-d <voidborne-d@users.noreply.github.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/packages/harness/deerflow/community/jina_ai/jina_client.py

@@ -38,6 +38,6 @@ class JinaClient:
 
             return response.text
         except Exception as e:
-            error_message = f"Request to Jina API failed: {str(e)}"
-            logger.exception(error_message)
+            error_message = f"Request to Jina API failed: {type(e).__name__}: {e}"
+            logger.warning(error_message)
             return f"Error: {error_message}"