feat: generalize monitor wait and apply stability fixes

[ndev-hoster]

Description

This PR introduces critical fixes for Ambxst shell startup synchronization, lockscreen stability, and resource cleanup.

1. Generalizing cli.sh Startup Monitor Wait Loop

• Problem: When starting up or logging in with an external monitor plugged in, a race condition occurred between Kanshi's screen configuration and Ambxst's UI initialization. Ambxst would start drawing elements while monitor states were changing, causing partial UI load failures (missing bar, dock, etc.).
• Fix: Replaced the hardcoded monitor check with a dynamic wait loop using hyprctl and jq.
  • Scans hyprctl monitors all -j to detect if an external monitor (non-eDP, non-LVDS, non-Virtual, non-HEADLESS) is physically connected.
  • If connected, it waits (up to 10 seconds, in 0.2s increments) for the external monitor to become active (disabled: false in hyprctl monitors -j), sleeping for an additional 1.0s to let the layout settle.
  • If no external monitor is physically connected (e.g. laptop-on-the-go), the loop is skipped instantly, preventing boot delay.
  • Ensures a clean slate on startup by cleaning up early-start quickshell and axctl daemons.

2. Enhancing LockScreen.qml Null Safety

• Problem: The session lockscreen would randomly crash when trying to capture a screenshot or retrieve the wallpaper frame path due to null properties.
• Fix:
  • Added null checks on GlobalStates.wallpaperManager.currentWallpaper before retrieving the frame path, wrapping it in a try-catch block.
  • Added null safety checks on root.screen for screencopyBackground.captureSource and guarded screencopyBackground.captureFrame() call.

3. Fixing Wallpaper.qml Resource Cleanup

• Problem: Memory leaks or dangling references could occur when switching wallpapers or destroying wallpaper views.
• Fix: Added Component.onDestruction clean up to set GlobalStates.wallpaperManager = null when the component is destroyed.