595 green, 0 warnings. Completes TASK 55 (slice 1, log rotation, shipped 2026-10-22).
- **`AlertClipCleanup`**: the default alert clip is materialised into `%TEMP%` for ffmpeg to read, and
nothing ever deleted it — one orphan per profile that ever played an alert. Now: delete this session's
file in `Shutdown`, and sweep `ytLive-alert-*.mp4` at startup for anything a crash left behind. Only
the prefix we own is touched; a directory is never deleted.
- **`DiskSpaceGuard`**: a recording that dies of a full disk is a trust breach, so the numbers are a
pure policy — refuse to start under **1 GB** (toast; the stream still starts, recording does not),
warn under **5 GB** at start ("about eighty minutes" at 8 Mbps ≈ 3.6 GB/h), and one mid-show warning
under **2 GB** — the last useful moment before the encoder fails for a reason it won't explain.
Unreadable drives (a USB stick that just left) return null and never block a running recording.
Tests are policy-level on purpose: filling a real drive is not a test. `DiskHygieneTests` proves the
sweep only removes our own files and that the thresholds behave at both ends.
