Fix thumbnail-less link posts rendering as a dead gray box.
- Detect link posts that Reddit returns without a
post_hint, which previously fell through every branch of the preview chain and rendered an empty.media-previewplaceholder - Restore the external-link action chip on those posts
- Add a hover/keyboard-focus state to the thumbnail-less link preview so it reads as interactive
- Add regression coverage for the missing-
post_hintcase and its inverse
Validation:
- 16/16 Bun tests pass
- All 19 Pug templates compile
- Biome checks pass
- Nix package build passes
- Docker amd64 smoke build and amd64/arm64 publish completed successfully
Full changelog: v0.2.3...v0.2.4