LR-EDIT-COLOR-TEMP: Kelvin white balance from Sony's white-balance presets

Sony ARWs of cameras without measured colour matrices were edited on the
relative scale (6500 K / 0 = as shot). Their SR2SubIFD stores the
multipliers of the camera's presets at 2500, 3200, 4500, 6000 and 8500 K;
lightcraft_raw::kelvin_presets reads the as-shot multipliers on the curve
through them and they take the spectral matrices' place in the #730
design (as-shot Kelvin and tint only; look, Bradford adaptation and the
pixel-identical legacy upgrade unchanged).

Covered: ILCA-99M2, ILCA-77M2, SLT-A33, DSC-RX10, ILCE-3500, ILCE-7S.
Kelvin-dial shots read back 3400 -> 3396, 5200 -> 5193, 4700 -> 4708,
5600 -> 5594 K; Shade 7493 K. Off-curve constants (isotherm tilt 0.74,
tint spacing 1) measured from the 14 Sony bodies with both spectral
matrices and presets.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/control-protocol.md

@@ -81,7 +81,8 @@ filmstrip is visible.
 
 White balance (`develop.set` with `wb.temp` / `wb.tint`, `develop.wb`, `develop.wbPick`) is in Kelvin and tint on
 raws with colour matrices — in the file (DNG) or measured for the camera model (`lightcraft_raw::spectral`; issue
-#730) — where As Shot reads the file's as-shot white; rendered files and raws without matrices use a relative scale
+#730) — and on raws whose white-balance presets give the scale (`lightcraft_raw::kelvin_presets`), where As Shot
+reads the file's as-shot white; rendered files and raws without matrices use a relative scale
 whose 6500 K / 0 is the as-shot look (the Edit panel shows it as −100..+100). The stored `wb` of such a Kelvin raw
 says `"scale": "kelvin"`; a partial settings JSON given to `develop.merge` or a preset whose `wb` sets `temp` / `tint`
 **without** `scale` keeps the relative meaning it always had (6500 = as shot) on every raw, so agents that mean