mount: refresh and evict hot dir cache (#8174)

* mount: refresh and evict hot dir cache

* mount: guard dir update window and extend TTL

* mount: reuse timestamp for cache mark

* Apply suggestion from @gemini-code-assist[bot]

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* mount: make dir cache tuning configurable

* mount: dedupe dir update notices

* mount: restore invalidate-all cache helper

* mount: keep hot dir tuning constants

* mount: centralize cache state reset

* mount: mark refresh completion time

* mount: allow disabling idle eviction

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

weed/mount/weedfs_dir_read.go

@@ -163,6 +163,8 @@ func (wfs *WFS) doReadDirectory(input *fuse.ReadIn, out *fuse.DirEntryList, isPl
 	if code != fuse.OK {
 		return code
 	}
+	wfs.inodeToPath.TouchDirectory(dirPath)
+	wfs.maybeRefreshDirectory(dirPath)
 
 	var dirEntry fuse.DirEntry