Close the only exploitable auth bypass: validate VerifyStatus signal sender
against fprintd's unique bus name. Fix fingerprint D-Bus lifecycle so devices
are properly released on verify-match and async restarts check the running
flag between awaits.
Security: num_msg guard in PAM callback, symlink rejection for background_path,
peek icon disabled, TOML parse errors logged, panic hook before logging.
Performance: blur and avatar textures cached across monitors, release profile
with LTO/strip.
Gaussian blur applied at texture load time when `background_blur` is
set in moonlock.toml. Refactored wallpaper loading from per-window
Picture::for_filename() to shared gdk::Texture pattern (matching
moonset/moongreet), avoiding redundant JPEG decoding on multi-monitor.