Format the face work with the workspace's own rustfmt

Not authored in this session. `cargo fmt --all` reformats every crate, so
running it while working on `dr-segment` picked up five files from the recent
face and library work that had been committed unformatted.

Committed on its own rather than swept into the change that happened to
produce it: the diff is pure whitespace, and mixed into a commit that alters
an algorithm it would be noise in exactly the place someone is trying to read
carefully. `cargo fmt --all -- --check` is a CI gate (tools/ci-local.sh), so
this had to land somewhere regardless.

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

ui/dr-ui/examples/face_native.rs

@@ -77,15 +77,9 @@ fn main() {
         };
         let (w, h) = (frame.width as usize, frame.height as usize);
 
-        let native = dr_ui::faces::index_native(
-            &mut detector,
-            &mut embedder,
-            &frame.rgba,
-            w,
-            h,
-            &options,
-        )
-        .unwrap_or_default();
+        let native =
+            dr_ui::faces::index_native(&mut detector, &mut embedder, &frame.rgba, w, h, &options)
+                .unwrap_or_default();
 
         // The old path, reproduced exactly: one buffer at 1024, used for both
         // detection and the crop.