style(simulation): cargo fmt the Global extent fix

Caught by the push gate, whose new named-failure block reported it as
'- cargo fmt' with the fix command — the information the old anonymous
'1 check(s) failed' withheld, on its first real outing.

No behaviour change.

Co-Authored-By: Claude <noreply@anthropic.com>

server/src/atlas/step_canvas.rs

@@ -1600,11 +1600,8 @@ pub fn serve_step_canvas_request(
         // The size this request will actually resolve to — the cache must be
         // consulted against THAT, not against the raw wire extent, because
         // Global fits the largest 2:1 canvas inside what was asked for.
-        let want = resolve_canvas_extent(
-            req.rung,
-            extent,
-            body_params.body_radius_km.unwrap_or(0.0),
-        );
+        let want =
+            resolve_canvas_extent(req.rung, extent, body_params.body_radius_km.unwrap_or(0.0));
         if let Some(canvas) = global_cache.get(&req.body_id, want) {
             return StepCanvasResponse {
                 body_id: req.body_id.clone(),