chore(search): wire Meilisearch — local compose + prod k8s manifests

Add a meilisearch service to the dev docker-compose (port 7700, persistent volume)
and MEILI_URL/MEILI_KEY (+ IIOS_CRED_KEY, IIOS_MEDIA_GC_INTERVAL_MS) to .env.example.
Add deploy/meilisearch.yaml — a ready-to-apply k8s Deployment/Service/PVC/Secret for
the ArgoCD prod stack (copy into k8s-pods/services/iios/), with wiring notes for the
iios-service env (MEILI_URL=http://meilisearch:7700, MEILI_KEY from the secret).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docker-compose.yml

@@ -29,5 +29,24 @@ services:
       timeout: 5s
       retries: 10
 
+  # Full-text message search. The service uses it when MEILI_URL is set (else search no-ops).
+  # Point the service at it with MEILI_URL=http://localhost:7700 + MEILI_KEY=<master key>.
+  meilisearch:
+    image: getmeili/meilisearch:v1.11
+    container_name: iios-meili
+    ports:
+      - "7700:7700"
+    environment:
+      MEILI_NO_ANALYTICS: "true"
+      MEILI_MASTER_KEY: ${MEILI_MASTER_KEY:-dev-meili-master-key}
+    volumes:
+      - iios_meili_data:/meili_data
+    healthcheck:
+      test: ["CMD-SHELL", "curl -sf http://localhost:7700/health || exit 1"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
 volumes:
   iios_postgres_data:
+  iios_meili_data: