Establish src-tauri/src/domain/ as the single source of truth for the
media model, with all Jellyfin translation isolated in from_jellyfin.rs.
Adds MediaKind enum and neutral duration_ms/image_id fields to MediaItem
as additive, defaulted dual-carry alongside the legacy Jellyfin-named
fields, so nothing breaks while the frontend migrates off them.
- domain/media.rs: canonical MediaKind (closed enum, replaces stringly
item_type), Default = Other so unknown/defaulted items are inert.
- domain/from_jellyfin.rs: total, panic-free item_type -> MediaKind
classification (all audited types + person subroles) and ticks->ms.
- MediaItem gains kind/duration_ms/image_id, populated at both mapping
seams (online to_media_item, offline cached_item_to_media_item) and
the synthesized-album/person sites.
- Regenerated bindings.ts: frontend now HAS the neutral model available.
Phase 1 of docs/specs/frontend-domain-model.md. No frontend behaviour
change yet; wire shape is a superset of before.
Rust 456 tests, frontend 644 tests, check + check:boundary all green.
dtourolle
55fa26377a