Put the coordinate-domain lens corrections into the graph

`lens.rs` has held a `Warp` trait, a composer and two implementations —
distortion and lateral chromatic aberration — since they were written, and
`compose_warps` was called by nothing outside its own tests. The corrections
existed, were correct, and never touched a photograph.

`EditGraph` now holds them, and `compose_full` emits them between the framing
prologue and the fetch. Distortion first, then CA: each warp receives the
position the previous one produced, and lateral CA is a magnification about
the optical axis of the *undistorted* frame, so measured on a barrel-distorted
one it would be fitted to a radius no profile describes.

They reach the panel the way framing already does — through `capabilities`.
That was the one open question and existing practice answered it: framing is
also not an `Operation`, also has parameters a photographer sets, and also
arrives through that list. Because `Preset::capture` walks the same list, the
sidecar, the clipboard and the undo stack carry a warp's parameters with
nothing registered anywhere, and no file under `ui/` names one (FR-DEV-3a).

`state()` destructures `EditGraph` field by field precisely so that a new
field cannot be forgotten, and it was not.

Chromatic aberration is the only thing that samples per channel, and
`splits_channels` is what keeps everything else from paying for it. Red and
blue are fetched from positions green is not — green is the reference and
never moves, so a wrong correction still leaves one channel sharp rather than
softening all three. With no CA in the chain the single-fetch path is emitted
instead.

The interpolating sampler is now chosen by framing *or* an active warp. Asking
framing alone would have nearest-neighboured a distortion correction on an
unstraightened frame, and that aliasing reads as a bad profile rather than as
a missing filter.

The warps go in the geometry invalidation key rather than the colour one: they
decide which source pixel a colour is read from, so a tile cached across a
distortion change would keep drawing the previous correction. The pipeline
cache needs nothing new — `hash_source` already covers the generated body, and
uniform values never enter it, so arming a warp recompiles and dragging it
does not. Both are asserted.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

ui/dr-ui/src/labels.rs

@@ -154,6 +154,12 @@ fn catalogued(key: &str) -> Option<&'static str> {
         // one for what it corrects means the two can sit in the same panel
         // without either having to be renamed to make room.
         "op.vignetting" => "Lens Vignetting",
+        // "Chromatic Aberration", not the "Aberration" `derive` would give.
+        // The bare word names a whole family of lens defects — coma, spherical,
+        // astigmatism — and this operation corrects exactly one of them. Under
+        // it sit sliders called "Red" and "Blue", which only make sense once
+        // the heading has said what is being separated.
+        "op.aberration" => "Chromatic Aberration",
 
         // Parameters
         "param.temperature" => "Temperature",