Move tray-related state holders out of lib.rs into a new
src-tauri/src/tray_runtime.rs:
- TrayState / TrayTooltip type aliases
- TrayPlaybackState newtype
- TrayMenuItems / TrayMenuItemsState
- TrayMenuLabels (+ Default impl) / TrayMenuLabelsState
- tray_state_icon helper
The actual tray builder + Tauri commands (try_build_tray_icon,
set_tray_tooltip, set_tray_menu_labels, toggle_tray_icon) already
lived in lib_commands/sync/tray.rs and continue to reach the types
through the existing super::* re-export chain.
lib.rs goes from 549 → 486 LOC. Behaviour-preserving — same managed
state, same Tauri State<T> registrations in run().
Psychotoxical