Slice 4. 607 green, 0 warnings. Clips remain **off by default** and, while off, the ring is never
constructed — so no reader thread and no encoder output exist until someone asks for the feature.
- **F10** (`HotkeyId.SaveClip`, default F10, remappable in the hotkey dialog) snapshots the ring, writes
the file, prunes to the retention count and toasts the name. Empty ring → "nothing to clip yet"
instead of a zero-byte file; clips off → says so and points at Settings.
- **Settings**: Enable, length (10 or 15, default 10), keep (3/4/5, default 3). Persisted in the layout
store and **coerced on load** — a bad stored value falls back to a legal one, so the ring can never be
sized for a length the UI cannot show.
- The ring is sized from length × tier bitrate × 1.25 and rebuilt if either changes; it is created at
session start and dropped at stop, so memory is only spent while a show is running.
- The drawer states the boundary in the creator's terms: "A capture, not an editor: for trimming,
captions or a library, use a video editor."
Still to come: the replay layer itself (play once then hide in Live, loop the kept clips elsewhere).
