perf(keywords): batch query resolution

[hubab1]

Summary

• resolve existing keyword queries in bounded bulk fetches instead of one fetch per keyword/storefront pair
• reconcile exact tracked-keyword identities at submit time, including saves from another SwiftData context
• preserve normalized duplicate handling, deterministic insertion order, save rollback, analytics, and refresh behavior

Testing

• focused AddKeywordsQueryResolverTests: 6 passed
• full macOS suite: 193 tests in 24 suites passed
• app build and launch verification passed

Attribution

Adapted from the query-resolution work in PR #8 by @akshaynexus. The implementation commit includes Akshay CM as a co-author.