feat(wiki): docs-lookup plugin against Quartz contentIndex

New maubot plugin that points at any Quartz-rendered docs site and
answers chat queries by full-text searching its emitted
/static/contentIndex.json. Default config targets docs.ariege.io
(castle-docs).

Commands:
  !ask <query>            search corpus; top-N hits with snippet + link
  !doc <slug-or-title>    open a specific page (fuzzy title match)
  !wiki / !wiki refresh   status / force re-index

Architecture:
- Periodic fetch (default 10 min) of /static/contentIndex.json
- In-memory inverted-ish scoring: title hit 5pt, content hit 1pt + freq
- No LLM — pure deterministic keyword search; RAG is future Phase 2b
- No DB — index is upstream-derived cache, repopulates on bot restart

Deployment posture: docs.ariege.io is served from cfaun alongside
maubot, so the bot hits it over the host's internal network — works
during WAN outages. base-config.yaml exposes docs_url + index_path
for adopters pointing at their own site.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

wiki/maubot.yaml

@@ -0,0 +1,9 @@
+maubot: 0.1.0
+id: dev.aiolabs.wiki
+version: 0.1.0
+license: AGPL-3.0-or-later
+modules:
+  - wiki
+main_class: WikiBot
+database: false
+config: true