[isihin-3]

Closes #59

Summary

Preserves search query and filter parameters when navigating between homepage search/filter results and game detail pages:

• Appends active search and filter parameters (q, chipset, performance, playMethod, genre) to GameCard links via buildGameCardHref.
• Updates the game detail page breadcrumb via buildGameBackLink to contextually link back to the search results (< Back to search results) or filtered list (< Back to games) instead of unconditionally resetting to /.
• Preserves search query parameters across permanent slug redirects.
• Keeps search query state synchronized when navigating via browser native Back and Forward buttons.

Verification

• Tested locally with bun run dev:server and bun run dev:vinext.
• bun run lint (0 errors, 0 warnings).
• bun run format:check (clean).
• bunx tsc --noEmit (clean at root and in packages/macgamingdb-server).
• bun run test (122 tests passing across 21 test files, including new unit tests for buildSearchQueryString, buildGameCardHref, and buildGameBackLink).
• bun run build:vinext (standalone output generated successfully).