Use native synchronous z-order binding (koffi) instead of async PowerShell
for overlay positioning, eliminating the 200-500ms delay that left the overlay
behind mpv after restore. Hide the overlay immediately when mpv is minimized
so the full show/reveal/z-order flow triggers cleanly on restore.
Also adds hover suppression after visibility recovery and window resize to
prevent spurious auto-pause, Windows secondary subtitle titlebar fix, and
z-order sync burst retries on geometry changes.
- switch Windows overlay tracking to native win32 polling with native owner and z-order helpers
- keep the visible overlay and stats overlay aligned across focus handoff, transient tracker misses, and minimize/restore cycles
- start the visible overlay click-through and hide the initial opaque startup frame until the tracked transparent state settles
- add a backlog task for the inconsistent mpv y-t overlay toggle after menu toggles
- Add default `f` fullscreen overlay binding and switch default AniSkip skip key to `Tab`
- Make character-dictionary auto-sync non-blocking at startup with tokenization gating for Yomitan mutations
- Add ordered startup OSD progress (checking/generating/updating/importing), refresh current subtitle on sync completion, and extend regression tests
