youtube feeder improvement

feeder-plugin/youtube-feeder/src/consts.rs

@@ -55,3 +55,28 @@ pub const MAX_REFS_PER_RECORDING: usize = 3;
 
 // MusicBrainz's published rate ceiling, from the crate that owns that client.
 pub use musicbrainz_feeder::consts::{MB_BURST, MB_RATE_PER_SEC, MB_TIMEOUT_SECS};
+
+/// Ceiling on raw free-text video hits emitted for one query.
+///
+/// The music paths thin their results with a *verification* — channel identity
+/// plus duration — and refuse everything that fails it. The raw tier has no
+/// such filter by construction, so the only bound available is a count. 20 is a
+/// search page's worth: enough for the section to be useful, few enough that
+/// one query does not pull a hundred thumbnails into the gateway's blockstore
+/// (`poster_url` is fetched **and seeded** by the core, unlike a `cover`
+/// locator, which stays lazy).
+pub const YT_VIDEO_SEARCH_MAX: usize = 20;
+
+/// Left half of a raw video tier record id (`yt~<videoId>`).
+///
+/// The music tier keys a record on `<mbRecordingId>~<videoId>` because the same
+/// video can legitimately be the reference for more than one recording. The raw
+/// tier has no such second axis — a video is itself and nothing else — so the
+/// left half is a constant, which makes the id a pure function of the video id
+/// and lets the gateway dedupe the same hit across different search terms.
+///
+/// ⚠ It must stay parseable by [`crate::youtube::split_track_record_id`]: the
+/// `~` split is what keeps `compute_outcomes` a zero-I/O pure function for both
+/// tiers. A left half that could collide with a MusicBrainz id would be a bug;
+/// `yt` cannot, since MBIDs are UUIDs.
+pub const VIDEO_RECORD_NS: &str = "yt";