Stop describing a base curve the pipeline no longer has

D19 retired the per-body base curve, moved the matrix ahead of the
edits and the film into the view transform's place, but a dozen doc
comments still listed the curve among what a pixel passes through, or
said the film skipped it. The detail stage's module doc still drew the
matrix after the edits and the last detail pass encoding, which the
view pass took over. The film crate's README gave the base curves as
its reason for being data, and the ops README's list of hand-written
nodes had neither the view transform nor three of the five kernels.

FR-MRG-2 gave the base curve as why the merge cuts below the profile;
the view transform is why now. The decision table still said colour
defaults were a per-body curve, and FR-DEV-3j said only the default
view transform skips a JPEG, where the node skips one whatever its
sliders say. frame-budget.md records the view pass as unmeasured.

core/dr-gpu/src/demosaic.rs

@@ -320,10 +320,11 @@ impl DemosaicedImage {
             color_matrix: IDENTITY_3X3,
             as_shot_wb: [1.0, 1.0, 1.0],
             // **The identity, and this is the whole reason the field is here
-            // rather than resolved further down.** A JPEG has already had its
-            // camera's base curve baked in by the camera; applying one again
-            // would render the rendering, crushing the shadows and flattening
-            // the highlights of an image that was already finished.
+            // rather than resolved further down.** A JPEG has already been
+            // rendered by the camera; the view transform skips a source
+            // flagged non-linear, since rendering the rendering would crush
+            // the shadows and flatten the highlights of an image that was
+            // already finished.
             non_linear: true,
             id: next_image_id(),
             frame: (width, height),
@@ -338,7 +339,7 @@ impl DemosaicedImage {
     /// what a merge writes. No demosaic; the samples are normalised by the
     /// file's black and white levels exactly as the demosaic kernel would
     /// normalise a photosite, and everything else — the matrix, the
-    /// balance, the body's base curve — is carried through as for a CFA
+    /// balance, the view transform — is carried through as for a CFA
     /// file, because the composite is developed as one photograph from the
     /// body that took its sources.
     pub fn from_linear_rgb16(ctx: &GpuContext, raw: &RawImage) -> Result<Self, GpuError> {