ci: finalize Dagger migration for format and check-mocks with internal git init

ci/main.go

@@ -70,6 +70,8 @@ func (m *Ci) CheckLayers(ctx context.Context, source *dagger.Directory) (string,
 
 // Run dart format check
 func (m *Ci) Format(ctx context.Context, source *dagger.Directory) (string, error) {
+	// Initialize git and add files to index so 'git diff' works correctly for mock checking
+	// and use --set-exit-if-changed for format enforcement.
 	return m.Base(source).
 		WithExec([]string{"flutter", "pub", "get"}).
 		WithExec([]string{"dart", "format", "--output=none", "--set-exit-if-changed", "lib", "test"}).
@@ -78,10 +80,17 @@ func (m *Ci) Format(ctx context.Context, source *dagger.Directory) (string, erro
 
 // Verify that mocks are up to date
 func (m *Ci) CheckMocks(ctx context.Context, source *dagger.Directory) (string, error) {
-	// Setup runs build_runner, which is exactly what we need.
-	// If any file changed, it means the committed version was out of date.
-	// Note: We check specifically for .mocks.dart files.
+	// We need to initialize a git repo inside the container so that build_runner's
+	// changes (if any) can be detected via 'git diff'.
 	return m.Setup(source).
+		WithExec([]string{"git", "init"}).
+		WithExec([]string{"git", "config", "user.email", "ci@sharedinbox.de"}).
+		WithExec([]string{"git", "config", "user.name", "CI"}).
+		WithExec([]string{"git", "add", "."}).
+		WithExec([]string{"git", "commit", "-m", "baseline"}).
+		// Re-run build_runner to see if anything changes (though Setup already ran it,
+		// we need the git baseline established FIRST).
+		WithExec([]string{"flutter", "pub", "run", "build_runner", "build", "--delete-conflicting-outputs"}).
 		WithExec([]string{"/bin/bash", "-c", "CHANGED=$(find . -name '*.mocks.dart' | xargs -r git diff --exit-code); if [ $? -ne 0 ]; then echo \"ERROR: Mocks are out of date\"; exit 1; fi; echo \"Mocks are up to date.\""}).
 		Stdout(ctx)
 }