Classify PermissionError as PermanentError instead of TransientError

PermissionError is a subclass of OSError, so it was caught by the
broad timeout/io handler and classified as transient. An unreadable
file would retry 5 times then DLQ — permissions don't fix themselves
without operator intervention.

Add an explicit PermissionError check before the OSError catch so
unreadable files go straight to the DLQ.

haiku_rag_slim/haiku/rag/ingester/workers/pipeline.py

@@ -60,6 +60,9 @@ def _classify(exc: BaseException) -> Exception:
     if isinstance(exc, FileNotFoundError):
         return PermanentError(f"file not found: {exc}")
 
+    if isinstance(exc, PermissionError):
+        return PermanentError(f"permission denied: {exc}")
+
     if isinstance(exc, asyncio.TimeoutError | TimeoutError | OSError):
         return TransientError(f"timeout/io: {exc}")
 

tests/ingester/test_pipeline.py

@@ -270,3 +270,12 @@ async def test_file_not_found_classified_as_permanent():
     client.create_document_from_source.side_effect = FileNotFoundError("gone")
     with pytest.raises(PermanentError, match="file not found"):
         await run_job(client, _job())
+
+
+@pytest.mark.asyncio
+async def test_permission_error_classified_as_permanent():
+    """An unreadable file should go straight to the DLQ, not retry."""
+    client = _mock_client()
+    client.create_document_from_source.side_effect = PermissionError("no access")
+    with pytest.raises(PermanentError, match="permission denied"):
+        await run_job(client, _job())