Doc audit: fix all broken links + correct stale facts across the KB

Fanned out 5 read-only doc-auditor subagents (one per service group) that
fact-checked the knowledge base against the live system + repo config,
researched official setup docs online, and verified progress. Applied:
- All 34 broken links fixed (real pages / external URLs / correct relative
  paths); 0 broken links remain. No .AGENTTRASH links (the 4 mentions are
  accurate descriptive text, not links).
- Fact-check fixes: Readarr retired (May 2026), Radarr v4->v6, Calibre
  9.2.1 live, Calibre-Web 0.6.25 live, Copyparty v1.20.21, LLM index
  ncmoe 38 + 786432 ctx, frank-default-small active (not frank-pp-worker),
  Hermes/SearXNG/Grafana hostnames, Loki/Alloy local images, Observability
  diagram (Promtail->Alloy), VLLM retired note, DFlash status, benchmark
  live-drift notes, Homepage test count 116.

docs/Infrastructure/Loki.md

@@ -8,7 +8,7 @@ Loki is the log aggregation backend of the observability stack. It stores and qu
 
 | Item | Value |
 |------|-------|
-| Image | `grafana/loki:latest` |
+| Image | `franksdank/loki:latest` (local build with a static busybox healthcheck) |
 | Port | 3100 (host) → 3100 (container) |
 | Mode | single-binary (all components in one process) |
 | Storage | filesystem (bind mount) |