fix(ci): replace diff --include with find-based comparison for generated files

The GNU diff in the CI container doesn't support --include flag; switch
to a find | while-read loop that diffs each matched file individually.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ci/main.go

@@ -511,10 +511,11 @@ func (m *Ci) CheckGenerated(ctx context.Context) (string, error) {
 		WithDirectory("/committed", m.checkSrc(), dagger.ContainerWithDirectoryOpts{Owner: "ci"}).
 		WithDirectory("/generated", fresh, dagger.ContainerWithDirectoryOpts{Owner: "ci"}).
 		WithExec([]string{"/bin/bash", "-c",
-			`if diff -rq --include='*.g.dart' --include='*.mocks.dart' /committed /generated; then ` +
-				`echo "Generated files are up to date."; ` +
-				`else echo "ERROR: Generated files are out of date — run: dart run build_runner build"; exit 1; ` +
-				`fi`}).
+			`stale=$(find /committed -name '*.g.dart' -o -name '*.mocks.dart' | ` +
+				`while IFS= read -r f; do rel="${f#/committed/}"; diff -q "$f" "/generated/$rel" >/dev/null 2>&1 || echo "$rel"; done); ` +
+				`if [ -n "$stale" ]; then ` +
+				`echo "ERROR: Generated files are out of date — run: dart run build_runner build"; echo "$stale"; exit 1; ` +
+				`else echo "Generated files are up to date."; fi`}).
 		Stdout(ctx)
 }