workspace: add position-based monitor selection

[cmihail]

Description:

Describe your PR, what does it fix/add?

This PR adds support for position-based monitor selection in workspace rules using the
monitor:position:XxY syntax.

Relates to #12305

Monitor IDs are assigned based on connection order, making them unreliable for multi-monitor
setups. Position-based selection enables deterministic workspace assignment regardless of hotplug
order.

Example usage for a triple-monitor setup:
workspace = 1, monitor:position:0x0, persistent:true
workspace = 2, monitor:position:1920x0, persistent:true
workspace = 3, monitor:position:3840x0, persistent:true

This is more reliable than using monitor IDs because:

• Monitor IDs depend on attachment order
• Position-based selection works consistently with monitor configurations like:
  monitor=eDP-1,preferred,0x0,1 # left monitor
  monitor=HDMI-A-1,preferred,1920x0,1 # middle monitor
  monitor=DP-1,preferred,auto-right,1 # right monitor

Implementation:

• Added position matching in CMonitor::matchesStaticSelector()
• Added CCompositor::getMonitorFromPosition() helper function
• Updated CConfigManager::getBoundMonitorForWS() to handle position-based selection
• Fallback to monitor ID 0 when position doesn't match any monitor

Is there anything you want to mention? (unchecked code, possible bugs, found problems,

breaking compatibility, etc.)

• Fully backward compatible - existing monitor:desc: and monitor:name syntax unchanged
• Integration tests added in hyprtester/src/tests/main/persistent.cpp
• Fallback behavior ensures graceful handling when position doesn't exist

Is it ready for merging, or does it need work?

Ready for merging. I tested this behavior on my Fedora 43 build manually and works as I expected

[cmihail]

Actually I found an edge case not yet supported by this configuration, i.e. if I want to assign workspaces to the most right monitor.

I will see if I can add an extra setting like r-1920x0 or 1920xb-1080 which will choose layouts starting from right/bottom instead of left/top