fix(ingest): address review round 1 (Literal kind + log tidy)

- escalation: EscalationDecision.kind is now Literal["hop","suppressed"] so ty
  catches a bad kind statically (and the processor branch is exhaustive).
- processor: simplify the suppressed-escalation log line (no longer repeats
  to_tier / tier).
- registry: clarify _tier_available's ignore_enabled drops the OCR-enabled gate
  specifically (a future per-tier gate would extend the condition).

Deck #324.

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

nextcloud_mcp_server/vector/processor.py

@@ -165,14 +165,12 @@ async def _parse_pdf_tier(
                 tier, decision.to_tier, decision.reason
             )
             logger.info(
-                "Escalation suppressed for %s %s->%s (reason=%s; %s disabled), "
-                "indexing at %s",
+                "Escalation suppressed for %s: %s->%s disabled (reason=%s), "
+                "indexing at current tier",
                 filename or "<bytes>",
                 tier,
                 decision.to_tier,
                 decision.reason,
-                decision.to_tier,
-                tier,
             )
         elif decision is not None:
             record_document_escalation(tier, decision.to_tier, decision.reason)