Following AGENTS.md's Never crash rules for the M3 / M4 additions:
- Cache Frames When Idle panicked (`clamp` with min > max) when the work area was inverted
(start set past the end); an empty work area now has nothing to cache.
- `file.newCompFromSelection`: the sequence overlap times the layer count overflowed for a huge
`overlapDuration` (wrapping to a wrong comp length without overflow checks); negative or
non-finite values fall back to 1 s and the product saturates. The lead item is read with
`get()` instead of indexing.
- Layer Settings' enablement reads the first selected layer with `first()`.
- Regression tests for both (each failed before the fix).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>