feat(hypr): cut over wallpaper ownership to Quickshell

[bhdai]

Companion cutover for bhdai/quickshell_config#108.

Summary

• remove the sole hyprpaper autostart command and delete its configuration
• leave an offline rollback tombstone at the former autostart site
• add non-repeating wallpaper next/previous IPC bindings
• advance the Quickshell submodule through the merged dashboard and wallpaper work in PRs #109–#114
• retain the installed hyprpaper package as the offline rollback provider

The issue names meh + W and meh + Shift + W, but this repo defines meh as Ctrl+Shift+Alt, which makes those chords identical. This implements the intended distinct base/Shift pair as Ctrl+Alt+W and Ctrl+Alt+Shift+W.

Supported wallpaper formats remain .jpg, .jpeg, .png, and .bmp. The accepted WebP/JPEG XL exclusion remains in force and this cutover adds no image dependency.

Verification

• node --test — 34 tests passed
• wallpaper service, dashboard geometry, and wallpaper interaction fixtures passed on Quickshell 0.3.0
• the remaining smoke-workflow fixtures passed, including repeated wallpaper transitions
• merged Quickshell PR #114 passed both the unit and full headless load jobs
• luac -p config/hypr/autostart.lua config/hypr/binds.lua
• live graphical session reported LockedHint=no before the Quickshell fast-forward
• live Quickshell advanced from 0949942 to ee2f5ec
• Wallpaper IPC resolves /home/dai/Pictures/wall/leaves.jpg
• while hyprpaper remains running, hyprctl layers reports both providers at 1920×1200 and quickshell:wallpaper belongs to the running Quickshell PID

Manual cutover still required

No display-backed visual result is claimed here.

• confirm the selected Quickshell image is visibly on the background
• confirm dashboard layout, picker pointer/keyboard behavior, crossfade, palette repaint, and desktop click-through
• confirm lock background, DPMS, hotplug, and mirror behavior
• reload/re-login and confirm the next/previous bindings fire once per press
• after visual confirmation, mask hyprpaper.service and stop the running hyprpaper process
• verify exactly one quickshell:wallpaper background per output and zero hyprpaper entries
• verify pgrep hyprpaper is empty and the unit is masked
• re-login and confirm hyprpaper stays stopped while the persisted Quickshell wallpaper returns
• prove the documented unmask/start/preload/bind rollback works offline