Add CI step to verify generated code is up-to-date

Runs the generator after restore and fails the build if there are any
uncommitted diffs, ensuring PRs always include freshly generated output.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jaredpar

.github/workflows/dotnet.yml

@@ -24,6 +24,11 @@ jobs:
       - name: Restore dependencies
         run: dotnet restore
 
+      - name: Verify generated code is up-to-date
+        run: |
+          dotnet run --project Src/Generate
+          git diff --exit-code || (echo "Generated code is out of date. Run 'dotnet run --project Src/Generate' and commit the results." && exit 1)
+
       - name: Build
         run: dotnet build --no-restore -bl