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-pipeline/src/sidecar.rs

@@ -67,9 +67,7 @@ use std::fmt;
 use std::fmt::Write as _;
 
 use crate::graph::EditGraph;
-use crate::mask::{
-    Falloff, MaskLayer, MaskSource, MaskStack, Morphology, Stroke, DEFAULT_FEATHER,
-};
+use crate::mask::{Falloff, MaskLayer, MaskSource, MaskStack, Morphology, Stroke, DEFAULT_FEATHER};
 use crate::preset::{resolve, Preset};
 
 /// Format version of the document itself.
@@ -662,7 +660,6 @@ impl Sidecar {
     }
 }
 
-
 /// Write one mask layer as its own block.
 ///
 /// The version uuid is repeated in the header rather than relying on the
@@ -1292,7 +1289,11 @@ mod tests {
         // else.
         assert_eq!(g.param(curve::ID, curve::P1_Y), Some(0.15));
         assert_eq!(g.param(curve::ID, curve::P3_Y), Some(0.85));
-        for channel in [curve::Channel::Red, curve::Channel::Green, curve::Channel::Blue] {
+        for channel in [
+            curve::Channel::Red,
+            curve::Channel::Green,
+            curve::Channel::Blue,
+        ] {
             for point in 0..curve::POINTS {
                 for axis in [curve::Axis::X, curve::Axis::Y] {
                     let id = curve::coordinate(channel, point, axis);