Add TOML config, playerctl dep, and media button defaults; bump to v1.1.0

- Switch config format from JSON to TOML (tomllib built-in on 3.11+,
  tomli fallback for 3.10) so the generated config can include comments
- Write an annotated config.toml on first run with descriptions for every
  knob/button and hints for all available actions
- Promote playerctl from optdepends to depends so media buttons work
  out of the box
- Default buttons 1–3 now pre-configured for playerctl previous/play-pause/next
- Rename contrib/config.example.json → config.example.toml with full
  TOML rewrite including per-knob LED colour override examples
- Log a migration hint when a legacy config.json is detected

.github/workflows/publish-aur.yml

@@ -53,7 +53,7 @@ jobs:
           	depends = python-pyserial
           	depends = python-pulsectl
           	depends = pipewire-pulse
-          	optdepends = playerctl: media key support via button commands
+          	depends = playerctl
           	optdepends = pulseaudio: alternative to pipewire-pulse
           	install = turnupd.install
           	source = ${PKGNAME}-${VERSION}.tar.gz::https://github.com/${{ github.repository }}/archive/refs/tags/v${VERSION}.tar.gz