Unified search adopts catalog rename

4178044: Adopt the catalog rename in unified search responses (monorepo issue #539 follow-up). releases search now reads response.catalog and renders the section as Catalog in human and markdown output (it covered products + standalone sources already; the header now matches the wire field). --type catalog is the canonical filter; --type products is accepted as a deprecated alias. The deprecated response.products field is still read as a fallback so older API deploys keep working — that fallback can be dropped once the alias is removed from the wire. Plugin docs and the releases-mcp skill updated to point at the new search / list_catalog / get_catalog_entry MCP tools.
ac4a443: Disable oxlint's no-underscore-dangle rule, surfaced by the 1.62 upgrade. The codebase deliberately uses leading-underscore identifiers for module-private state (_dataDir, _apiUrl, _apiKey, _admin); the rule's complaints aren't actionable. Keeps lint output clean and matches the same change in the monorepo for cross-repo consistency. CI-only; no runtime change.