feat(display): Fix and implement display auto-switching with JSON profile storage

[DK0280705]

The display auto-configuration feature was previously broken and explicitly disabled throughout the codebase — the UI toggle was hidden, the IPC toggleAuto command returned a hardcoded error, and the feature never ran at startup. This PR fixes all of that and delivers a fully working auto-switching system backed by a new compositor-neutral JSON profile format.

Changes:

• Profiles are now stored as compositor-neutral JSON. Compositor-specific config files (Hyprland .conf, Niri .kdl, DWL .conf) are generated from this JSON at apply time, unifying profile logic across compositors.
• DisplayConfigState is force-initialized at shell startup (DMSShell.qml) so auto-config runs on login.
• IPC toggleAuto fixed. Previously returned a hardcoded error, now properly toggles SettingsData.displayProfileAutoSelect, persists it, and calls autoSelectProfile().
• IPC status fixed. It was hardcoded to report auto: "off"; now reflects the real setting.
• The auto-select toggle is visible and functional, wired to SettingsData.displayProfileAutoSelect and triggering applyAutoConfig() on enable.
• Profile controls disabled during auto-select. The new/delete/edit buttons and profile dropdown are disabled while auto-select is on to prevent conflicts.
• "Edit Monitors" button. New toolbar button opens a per-profile monitor inclusion dialog via getProfileMonitorInclusion().
• Dropdown shows "Auto" when auto-select is active, the profile dropdown displays "Auto" via a reactive Binding.
• Added canDisableOutput() to prevent disabling the last active monitor.
• Profiles are validated to ensure at least one output is enabled. If all outputs are somehow disabled, the first is re-enabled automatically.

[bbedward]

Have you tested this on niri? With hot plugging displays. The reason it was temp disabled mainly was because of that, there would be crashes or display freezes on resume I think from some race between niri and dms writing display configurations.

[DK0280705]

Have you tested this on niri? With hot plugging displays. The reason it was temp disabled mainly was because of that, there would be crashes or display freezes on resume I think from some race between niri and dms writing display configurations.

Yes, actually i only used niri to test automatic display configuration, so i don't know if this going to work on hyprland or dwl/mango too.

I'm using this configuration for a while and there are no problems so far. Probably only when i suddenly unplug my external monitor from my laptop, some electron apps like vscode or discord freeze then crash, but that's not from the dms side as they also crash when i test with kanshi.

I don't think the problem comes from the race between niri and dms(?)
Iirc the previous code creates callback loop between niri state and display config state. Also DisplayConfigState was not initialized at startup, so auto profile changes won't work until you open settings.