site: rename "finds" superpost collection to "bundles"
Disambiguates the one-letter `find` (item) vs `finds` (roundup) split that
kept causing confusion. Audience-facing now: `/bundles/<slug>/`, "Bundle"
labels in home/footer/search.
Internals: `getCollection('finds')` → `('bundles')`, `Entry.type 'finds'`
→ `'bundle'`, `OgFallback 'finds'` → `'bundles'`, `findListMosaic` →
`bundleMosaic`, `FindsPost` → `Bundle`, `findsReferencing` →
`bundlesReferencing`. Build script + generated mosaic dir follow
(`scripts/build-bundle-mosaics.mjs`, `src/generated/bundle-mosaics/`).
Skills `build-finds` → `build-bundle`, `cluster-finds` →
`cluster-bundles`. The `find` collection (individual items) is unchanged.
No URL redirects: low external-link surface area.
rzen
049c6c5377