tailscale: update tailfs file and package names (#11590)

This change updates the tailfs file and package names to their new
naming convention.

Updates #tailscale/corp#16827

Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>

drive/driveimpl/dirfs/stat.go

@@ -0,0 +1,30 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package dirfs
+
+import (
+	"context"
+	"io/fs"
+	"os"
+
+	"tailscale.com/drive/driveimpl/shared"
+)
+
+// Stat implements webdav.FileSystem.
+func (dfs *FS) Stat(ctx context.Context, name string) (fs.FileInfo, error) {
+	nameWithoutStaticRoot, isStaticRoot := dfs.trimStaticRoot(name)
+	if isStaticRoot || shared.IsRoot(name) {
+		// Static root is a directory, always use now() as the modified time to
+		// bust caches.
+		fi := shared.ReadOnlyDirInfo(name, dfs.now())
+		return fi, nil
+	}
+
+	child := dfs.childFor(nameWithoutStaticRoot)
+	if child == nil {
+		return nil, &os.PathError{Op: "stat", Path: name, Err: os.ErrNotExist}
+	}
+
+	return shared.ReadOnlyDirInfo(name, dfs.now()), nil
+}