Caddy consolidation: single Caddy on dankclaw fronts both hosts

Per user direction, Caddy runs only on dankclaw. It fronts every
service on both hosts: local services by container name, quadlet
services by published LAN port, dankserver services by published LAN
port (192.168.0.235:PORT).

- dankclaw/Caddyfile: merged vhost list (was: two Caddyfiles, one per
  host). gitea's single vhost moves in from the retired gitea-caddy
  quadlet (option B). Upstreams fixed to live reality: gitea :3000,
  search :8081 (gluetun), chat :3005 (open-webui quadlet), media
  services via 192.168.0.235. Retired: llms (open-webui on dankserver
  is removed; chat is its successor), the dankserver homepage (302 to
  the shared one).
- dankserver/Caddyfile, dankclaw/gitea/Caddyfile: deleted (git rm).
- dnsmasq addn-hosts: every name -> 192.168.0.143 (the one Caddy
  host); no .235 records, no llms.
- compose.yaml: removed the openwebui/postgres/gitea services (they
  are quadlets now); caddy service mounts the rendered Caddyfile from
  /home/dank/Containers/caddy, healthcheck probes the bare-IP
  catch-all (302).
- deploy.sh: per-target logic (dankserver = pull-only, health via the
  shared Caddy at 192.168.0.143); renders CADDY_BASICAUTH_HASH from
  the host .env into the mounted Caddyfile.
- .env.example: CADDY_BASICAUTH_HASH on dankclaw; Porkbun block
  dropped from dankserver (its Caddy is gone); SEARXNG_BASE_URL to
  the flat name; stale OPENAI_* block dropped (quadlet is
  self-contained).
- tests: caddyfile.bats now asserts the single-Caddyfile invariant;
  dnsmasq.bats cross-checks vhosts -> .143 and the retired names.

dankclaw/gitea/Caddyfile

@@ -1,7 +0,0 @@
-# Gitea stack Caddyfile (dedicated Caddy container, quadlet-managed).
-# Lives on the host at /opt/gitea/data/caddy/Caddyfile.
-# Upstream is the quadlet container name gitea-server (port 3000 inside).
-
-gitea.franksdank.cloud {
-    reverse_proxy gitea-server:3000
-}