Add explicit force replacement workflow

internal/storage/fake/backend.go

@@ -205,6 +205,41 @@ func (b *Backend) DeleteManagedBundle(ctx context.Context, bundlePath string, ma
 	return nil
 }
 
+func (b *Backend) DeletePrefix(ctx context.Context, prefix string, opts storage.DeleteOptions) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	if err := storage.ValidatePrefix(prefix); err != nil {
+		return err
+	}
+	if prefix != "" && !b.exists(prefix) && !b.hasChild(prefix) {
+		if opts.IgnoreMissing {
+			return nil
+		}
+		return storage.NewError(storage.OpDeletePrefix, backendName, prefix, storage.ErrNotFound, nil)
+	}
+	for path := range b.files {
+		if path == prefix || entryBelow(prefix, path) {
+			delete(b.files, path)
+		}
+	}
+	for path := range b.symlinks {
+		if path == prefix || entryBelow(prefix, path) {
+			delete(b.symlinks, path)
+		}
+	}
+	for path := range b.dirs {
+		if path != "" && (path == prefix || entryBelow(prefix, path)) {
+			delete(b.dirs, path)
+		}
+	}
+	if opts.PruneEmptyDirs {
+		b.pruneEmptyParents(parentOf(prefix))
+	}
+	b.dirs[""] = struct{}{}
+	return nil
+}
+
 func (b *Backend) ensureParents(path string) {
 	parent := parentOf(path)
 	for parent != "" {