docs: three dangling links, and a gate so they cannot accumulate

The vault is the project's source of truth, so a link to a page that does not
exist is a promise the repo cannot keep. Three were dangling:

- Dankclaw/Gitea.md pointed twice at dankclaw/compose.yaml — **which this
  session retired**. The clean cutover obligation from my own change: the page
  now describes the unit that publishes 3000 and the canonical Caddy unit, and
  records why the compose file is gone.
- Dankclaw/Hermes-Dashboard.md linked [[LAN DNS]]; the page is [[LAN-DNS]].
- LLM/frank-medium-radiance-mxfp4.md linked [[Observability on Dankclaw]]; the
  page is [[Observability]].

scripts/check-vault-links.py + a seam keep it that way. The checker models
Obsidian's rules, which took three corrections to get right — and each was a
false positive that would have sent me editing healthy docs:

  1. Wikilinks are case-insensitive. A case-sensitive matcher reported 45
     breaks; 39 were `[[qBittorrent]]` vs qbittorrent.md.
  2. `[[folder/Note]]` resolves by path suffix, not by stem.
  3. `%20` in a markdown link is URL-encoding, not a filename.

Validating the linter against the resolver it models is the prerequisite for
trusting any of its output — the same discipline that caught a bad assertion of
my own earlier tonight.

serverAppConfigs-docs/LLM/frank-medium-radiance-mxfp4.md

@@ -426,8 +426,8 @@ scraped — Prometheus has `frank-medium` and `frank-large` jobs
 `vllm:kv_cache_usage_perc` (per-card pool fill), `vllm:num_requests_waiting`
 (queue depth), `rate(vllm:prefix_cache_hits_total[5m]) /
  rate(vllm:prefix_cache_queries_total[5m])` (whether pinned conversations are
-served warm), and the request-latency histograms. See
-[[Observability on Dankclaw]], and one Grafana dashboard reads them
+served warm), and the request-latency histograms. See [[Observability]], and one
+Grafana dashboard reads them
 (**LLM fleet — capacity and reuse**).
 
 Five rules watch this service (`shared/prometheus/rules/llm-fleet.yml`): pool