Format the tree the way the gate asks for it

`cargo fmt --check` is a required step and had drifted across 45 files. Most of
it arrived this week: several operations were written in parallel worktrees and
merged by hand, and a hand-merge resolves conflicts without ever running the
formatter over the result.

No behaviour changes — this is `cargo fmt --all` and nothing else, kept as its
own commit so the next reader can skip it wholesale rather than search it for
one that matters.

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

core/dr-gpu/tests/base_curve.rs

@@ -62,9 +62,7 @@ fn rendered_level(ctx: &GpuContext, level: u16, curve: BaseCurve) -> u8 {
         .expect("demosaic");
     let shader = EditGraph::default_chain().compose();
     let mut adjust = AdjustPass::new(ctx);
-    adjust
-        .render(&source, &shader, SIZE, SIZE)
-        .expect("render");
+    adjust.render(&source, &shader, SIZE, SIZE).expect("render");
     let (pixels, _, _) = adjust.export_pixels().expect("readback");
     let centre = ((SIZE / 2) * SIZE + SIZE / 2) * 4;
     pixels[centre as usize]