Fix CI workflow formatting command

Replace 'flutter format' with 'dart format' as the format command was moved to the Dart SDK in Flutter 3.x. This fixes the "Could not find a command named 'format'" error in the CI pipeline.

Co-authored-by: jwinarske <[email protected]>

Author: Copilot

.github/workflows/build.yml

@@ -25,7 +25,7 @@ jobs:
         run: flutter analyze
 
       - name: Check formatting
-        run: flutter format --set-exit-if-changed lib/
+        run: dart format --set-exit-if-changed lib/
 
   test:
     name: Run Tests