feat(search): add meilisearch engine foundation

configs/config.yaml

@@ -45,6 +45,14 @@ rate_limit:
   requests_per_minute: 100  # max requests per client IP per window
   window_seconds: 60        # sliding window duration in seconds
 
+search:
+  # Chatwoot parity target. Use "db" only for explicit local fallback.
+  engine: "meilisearch"
+  host: "http://localhost:7700"
+  api_key: ""
+  index_prefix: "gochat_"
+  timeout_seconds: 5
+
 saml:
   enabled: false  # SAML 2.0 SSO — enable for enterprise IdP integration
   # IdP metadata: provide URL or inline XML (URL preferred for auto-refresh)
@@ -60,4 +68,4 @@ saml:
     email: "email"            # SAML attribute → GoChat email field
     display_name: "displayName"  # SAML attribute → GoChat name field
     first_name: "firstName"    # SAML attribute → first name component
-    last_name: "lastName"     # SAML attribute → last name component
+    last_name: "lastName"     # SAML attribute → last name component