fix(ingest): suppress misleading batch-fallback warn for in-cluster rung

Address claude-review round 3 on #922:

- Important: _process_batch emitted "no gateway backend (provider=mistral or
  EMBEDDING_GATEWAY_URL unset)" for the gateway_only in-cluster rung, where the
  gateway IS configured — sending operators chasing a non-existent config
  problem. The real reason is "in-cluster GPU is synchronous-only; batch is the
  upstream path". Guard the warning with `if not self._gateway_only`. Extended
  test_gateway_only_processor_never_uses_batch_mode to drive _process_batch and
  assert _batch_fallback_warned stays False.
- Nits: refresh stale ladder in escalation.py module docstring
  (fast->structured->ocr-incluster->ocr-upstream); fix "minimum='ocr'" ->
  "ocr-incluster" in a test docstring; rename stale tier="ocr" ->
  "ocr-upstream" in test_process_tier_oversize_fails_fast.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

nextcloud_mcp_server/document_processors/escalation.py

@@ -2,7 +2,7 @@
 
 The escalation ladder is the cheapest-first ordering of extraction tiers:
 
-    fast  ->  structured  ->  ocr   ( ->  llm, reserved)
+    fast  ->  structured  ->  ocr-incluster  ->  ocr-upstream   ( ->  llm, reserved)
 
 It mirrors the ``tier`` vocabulary documented on
 :meth:`DocumentProcessor.tier <.base.DocumentProcessor.tier>` and the

nextcloud_mcp_server/document_processors/ocr.py

@@ -499,10 +499,15 @@ class OcrProcessor(DocumentProcessor):
             return None
         client = await self._get_batch_client()
         if client is None:
-            self._batch_fallback(
-                "no gateway backend (provider=mistral or EMBEDDING_GATEWAY_URL unset)",
-                filename,
-            )
+            # The in-cluster (gateway_only) rung returns None here BY DESIGN — the
+            # GPU is synchronous-only, batch is the upstream Mistral path — so don't
+            # emit the "no gateway backend" warning (the gateway IS configured; that
+            # warning would send an operator chasing a non-existent config problem).
+            if not self._gateway_only:
+                self._batch_fallback(
+                    "no gateway backend (provider=mistral or EMBEDDING_GATEWAY_URL unset)",
+                    filename,
+                )
             return None
 
         # Lazy import: keep the vector/DB stack off the document_processors load

tests/unit/test_ocr_processor.py

@@ -467,6 +467,24 @@ async def test_gateway_only_processor_never_uses_batch_mode(monkeypatch):
     assert await incluster._get_batch_client() is None
     assert called["n"] == 0  # short-circuited before building anything
 
+    # _process_batch returns None for the gateway-only rung WITHOUT emitting the
+    # misleading "no gateway backend" warning (the gateway IS configured; the rung
+    # is simply synchronous-only). _batch_fallback_warned stays False to prove it.
+    result = await incluster._process_batch(
+        b"%PDF-1.7",
+        "application/pdf",
+        "x.pdf",
+        dict(_IDENTITY),
+        _settings(
+            document_ocr_mode="batch",
+            document_ocr_provider="gateway",
+            embedding_gateway_url="https://gw",
+            document_ocr_incluster_model="surya/surya-ocr-2",
+        ),
+    )
+    assert result is None
+    assert incluster._batch_fallback_warned is False
+
     upstream = ocr.OcrProcessor()  # gateway_only=False
     assert await upstream._get_batch_client() is not None
     assert called["n"] == 1

tests/unit/test_registry_tiering.py

@@ -479,7 +479,9 @@ async def test_process_tier_oversize_fails_fast(monkeypatch):
         reg_mod, "get_settings", lambda: _Settings(max_pdf_size_mb=0.001)
     )
     r = _registry((_Fake("ocr-upstream", "ocr-upstream"), 5))
-    res = await r.process_tier(b"x" * 4096, "application/pdf", "big.pdf", "ocr")
+    res = await r.process_tier(
+        b"x" * 4096, "application/pdf", "big.pdf", "ocr-upstream"
+    )
     assert res.success is False
     assert res.metadata["parse_failed_reason"] == "oversize"
 
@@ -724,7 +726,7 @@ def test_evaluate_escalation_terminal_when_ocr_unregistered_and_off(monkeypatch)
 def test_evaluate_escalation_empty_suppressed_even_when_structured_registered(
     monkeypatch,
 ):
-    """empty_text uses minimum='ocr', so it skips structured even when structured
+    """empty_text uses minimum='ocr-incluster', so it skips structured even when structured
     IS registered: with OCR off it suppresses to ocr, never hops to structured
     (a text extractor can't conjure text from a raster scan)."""
     monkeypatch.setattr(reg_mod, "record_document_classification", MagicMock())