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/tone_curve.rs

@@ -24,7 +24,9 @@ fn ctx() -> Option<GpuContext> {
 /// The centre pixel's red, green and blue, after `graph` has run over flat
 /// mid-grey.
 fn rendered(ctx: &GpuContext, graph: &EditGraph) -> (u8, u8, u8) {
-    let data: Vec<u8> = (0..SIZE * SIZE).flat_map(|_| [128, 128, 128, 255]).collect();
+    let data: Vec<u8> = (0..SIZE * SIZE)
+        .flat_map(|_| [128, 128, 128, 255])
+        .collect();
     let source = DemosaicedImage::from_rgba8(ctx, &data, SIZE, SIZE).expect("upload");
 
     // Composed the way the display path composes it. A curve that generates
@@ -44,11 +46,7 @@ fn rendered(ctx: &GpuContext, graph: &EditGraph) -> (u8, u8, u8) {
 /// an edit.
 fn lifted(channel: Channel) -> EditGraph {
     let mut graph = EditGraph::default_chain();
-    graph.set_param(
-        curve::ID,
-        curve::coordinate(channel, 2, Axis::Y),
-        0.75,
-    );
+    graph.set_param(curve::ID, curve::coordinate(channel, 2, Axis::Y), 0.75);
     graph
 }
 
@@ -62,7 +60,10 @@ fn the_master_curve_lifts_every_component_together() {
     let (r0, g0, b0) = rendered(&ctx, &EditGraph::default_chain());
     let (r, g, b) = rendered(&ctx, &lifted(Channel::Master));
 
-    assert!(r > r0, "the master curve did not lift the image: {r} vs {r0}");
+    assert!(
+        r > r0,
+        "the master curve did not lift the image: {r} vs {r0}"
+    );
     // Grey in, grey out: the master curve is applied as a ratio over
     // luminance, so it changes tone and not hue. A tolerance of one code
     // value, because the components travel through the ratio separately and