added comments feature.
- this makes sure the user has the ability to comment on a certain find.
it includes functionality to the api-sync layer so that multiple
components can stay in sync with the comments state.
- it also added the needed db migrations to the finds
- it adds some ui components needed to create, list and view comments
Add VideoPlayer and LikeButton components with optimistic UI and /server
endpoints for likes. Update media processor to emit WebP and JPEG
fallbacks, store fallback URLs in the DB (migration + snapshot), add
video placeholder asset, and relax CSP media-src for R2.
