feat(api): on-write search reindex after catalogue writes (#17)

Wire best-effort Meilisearch index sync into the admin write paths
(create/update/delete/set_fields/set_visibility). Adds
SearchClient::sync_object (reindex if the object exists, remove if gone —
one uniform path), an optional AppState.search client, and a reindex
helper that logs failures via tracing without failing the committed
write. Server gains MEILI_URL/MEILI_MASTER_KEY/MEILI_INDEX config;
search stays disabled (no-op) when unset. reindex_all remains the
recovery path.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -82,6 +82,7 @@ dependencies = [
  "db",
  "domain",
  "http-body-util",
+ "search",
  "serde",
  "serde_json",
  "sqlx",
@@ -90,7 +91,9 @@ dependencies = [
  "tower",
  "tower-sessions",
  "tower-sessions-sqlx-store",
+ "tracing",
  "utoipa",
+ "uuid",
 ]
 
 [[package]]
@@ -1969,6 +1972,7 @@ dependencies = [
  "domain",
  "reqwest",
  "rpassword",
+ "search",
  "serde_json",
  "sqlx",
  "temp-env",