fix(infra): expose Meilisearch via search.libnovel.cc for homelab runner indexing

- Add search.libnovel.cc Caddy vhost proxying to meilisearch:7700
- Pass MEILI_URL + MEILI_API_KEY from Doppler into homelab runner
- Set GODEBUG=preferIPv4=1 to work around missing IPv6 route on homelab
- Update comments to reflect runner now indexes books into Meilisearch

homelab/runner/docker-compose.yml

@@ -8,7 +8,8 @@
 #   - RUNNER_WORKER_ID=homelab-runner-1  (unique, avoids task claiming conflicts)
 #   - MINIO_ENDPOINT/USE_SSL → storage.libnovel.cc over HTTPS
 #   - POCKETBASE_URL          → https://pb.libnovel.cc
-#   - MEILI_URL/VALKEY_ADDR   → unset (not exposed publicly; not needed by runner)
+#   - MEILI_URL               → https://search.libnovel.cc (Caddy-proxied)
+#   - VALKEY_ADDR             → unset (not exposed publicly)
 #   - RUNNER_SKIP_INITIAL_CATALOGUE_REFRESH=true
 
 services:
@@ -30,9 +31,12 @@ services:
       MINIO_PUBLIC_ENDPOINT: "${MINIO_PUBLIC_ENDPOINT}"
       MINIO_PUBLIC_USE_SSL: "${MINIO_PUBLIC_USE_SSL}"
 
-      # ── Meilisearch / Valkey — not exposed, disabled ────────────────────────
-      MEILI_URL: ""
+      # ── Meilisearch (via search.libnovel.cc Caddy proxy) ────────────────────
+      MEILI_URL: "${MEILI_URL}"
+      MEILI_API_KEY: "${MEILI_API_KEY}"
       VALKEY_ADDR: ""
+      # Force IPv4 DNS resolution — homelab has no IPv6 route to search.libnovel.cc
+      GODEBUG: "preferIPv4=1"
 
       # ── Kokoro TTS ──────────────────────────────────────────────────────────
       KOKORO_URL: "${KOKORO_URL}"