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/command/fuse_std.go

@@ -157,6 +157,13 @@ func runFuse(cmd *Command, args []string) bool {
 			} else {
 				panic(fmt.Errorf("cacheMetaTtlSec: %s", err))
 			}
+		case "dirIdleEvictSec":
+			if parsed, err := strconv.ParseInt(parameter.value, 0, 32); err == nil {
+				intValue := int(parsed)
+				mountOptions.dirIdleEvictSec = &intValue
+			} else {
+				panic(fmt.Errorf("dirIdleEvictSec: %s", err))
+			}
 		case "concurrentWriters":
 			i++
 			if parsed, err := strconv.ParseInt(parameter.value, 0, 32); err == nil {