Introduces a ScheduledTask mechanism that periodically calls rclone RC
vfs/refresh to keep directory listing caches warm (no file downloads),
with two-level config (global default + per-share override). Adds
dir-refresh status badges and timestamps to the web UI shares tab and
CLI status output, following the same pattern as warmup/warmed.
- src/scheduler.rs: New generic ScheduledTask runner with generation-based
cancellation and parse_interval() helper
- src/rclone/rc.rs: Add vfs_refresh() RC API call
- src/config.rs: Add DirRefreshConfig, per-share dir_refresh_interval
override, effective_dir_refresh_interval() resolution method
- src/config_diff.rs: Track dir_refresh_changed for hot-reload
- src/daemon.rs: Track per-share last_dir_refresh timestamps (HashMap),
add dir_refresh_ago_for() helper and format_ago()
- src/supervisor.rs: spawn_dir_refresh() per-share background threads,
called on startup and config reload
- src/web/api.rs: Expose dir_refresh_active + last_dir_refresh_ago in
ShareStatusResponse
- src/web/pages.rs: Populate dir_refresh_active + last_dir_refresh_ago
in ShareView and ShareDetailView
- templates/web/tabs/shares.html: DIR-REFRESH badge (yellow=pending,
green=N ago) in health column; Dir Refresh row in detail panel
- templates/web/tabs/config.html: Dir Refresh section and per-share
interval field in interactive config editor
- src/cli/status.rs: Append Dir-Refresh suffix to mount status lines
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>