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