test(ingest): use https test gateway URLs; doc fixes (review round 6)

Resolves the SonarCloud quality gate (new_security_hotspots_reviewed) — the 7
TO_REVIEW hotspots were all `http://gw` fake gateway URLs in test_ocr_processor.py
flagged "use https". Switched the test fixtures to `https://gw` (identical for a
fake URL) so no new hotspots remain to review; all other gate conditions already
passed.

Also address claude-review round 6:
- Stale test docstring: "suppresses to ocr" -> "suppresses to the cheapest
  registered OCR rung (here ocr-upstream)".
- OcrProcessor.__init__: comment that the upstream-shaped defaults are
  test/bare-construction convenience only; app wiring always passes args
  explicitly.

Left as-is (reviewer agreed): the `ocric=` signature abbreviation (opaque but
stable; renaming would invalidate dead-letter retries).

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

tests/unit/test_registry_tiering.py

@@ -751,9 +751,10 @@ 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-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)."""
+    """empty_text uses minimum='ocr-incluster', so it skips structured even when
+    structured IS registered: with OCR off it suppresses to the cheapest registered
+    OCR rung (here ocr-upstream, the only one registered in this test), never hops
+    to structured (a text extractor can't conjure text from a raster scan)."""
     monkeypatch.setattr(reg_mod, "record_document_classification", MagicMock())
     r = _registry(
         (_Fake("fast", "fast"), 20),