refactor(worker): trim observability helper docstring; clarify test fake

- Collapse _init_worker_observability's docstring to one line; the WHY moves
  to a concise inline comment (per review).
- Note that _fake_settings.ingest_queue is unused by the helper (test realism).

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

nextcloud_mcp_server/cli.py

@@ -291,16 +291,9 @@ def run(
 
 
 def _init_worker_observability(settings: Settings) -> None:
-    """Configure logging, metrics, and tracing for the ingest worker.
-
-    Mirrors the observability bootstrap the API pod performs in its lifespan
-    (``app.py``), but for the standalone ``worker`` entrypoint which never runs
-    uvicorn. Without this the worker emits plain-text logs and serves no
-    ``/metrics`` endpoint, so the astrolabe_* document-pipeline metrics and the
-    ``document_processor.parse`` spans (recorded in the shared registry/processor
-    code the worker executes) stay invisible in external split-worker mode
-    (Deck #310 / #175).
-    """
+    """Configure logging, metrics, and tracing for the standalone ingest worker."""
+    # Mirrors app.py's lifespan bootstrap; without it the worker's astrolabe_*
+    # metrics and document_processor.parse spans are invisible in external mode.
     # Structured logging first, so every subsequent startup line is JSON like
     # the API's — the worker entrypoint never went through uvicorn's log_config.
     setup_logging(

tests/test_cli.py

@@ -339,7 +339,7 @@ def _fake_settings(**overrides):
     real Settings.__post_init__ validation/derivation.
     """
     base = dict(
-        ingest_queue="postgres",
+        ingest_queue="postgres",  # for realism / worker() gating; unused by the helper
         log_format="json",
         log_level="INFO",
         log_include_trace_context=True,