Reworks mpdq around station-based queue building and script-local configuration, with cleaner MPD integration and updated docs.

  - Adds station mode, bundled station configs, bumper/tuning support, and remote
    filesystem handling
  - Prefers script-local config/cache/state paths while keeping XDG-compatible
    fallbacks
  - Standardizes MPD host/password handling across the script and fixes station
    selection and -c file handling
  - Improves exhaustion handling with escalating emergency log rotation and
    multiple queue-selection bug fixes
  - Removes obsolete metadata-tool dependency paths in favor of MPD/MPC data
  - Refreshes help, README, changelog, example config handling, and ignore rules
  - Adds bpm_to_stickers.sh and related station/audio resources