Review follow-up to the vignetting fit fix:
- `proxies` applies the embedded vignetting gain before it moves the sensor
into the camera JPEG's lens geometry, so a warped proxy pixel gets the gain
of the position it samples, as the render applies it.
- `alignment` reads NaN pixels (outside a lens-warped proxy) as missing. The
`max(1e-4)` turned them into black, a false edge along the border, and the
warped candidate lost on wide-angle RAFs with barrel distortion.
- Tests: the colour fit gets the embedded lens, the vignetting is applied
before the warp, and alignment ignores missing pixels.
27 + 60 X-S10 RAFs: mean ΔE00 unchanged (3.06, 2.55 -> 2.54), none worse by
more than 0.02.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
