Add action to toggle Show Layout Bounds in Compose UI

[rock3r]

This adds an action to the ui-inspector module that toggles the showLayoutBounds value for all currently attached ComposePanels. It also registers an AWT hierarchy listener, if the toggle is on, to capture when a new ComposePanel is added to the hierarchy and make sure the setting is respected in cases where panels are detached and then re-attached (the setting is lost when the panel is detached as it disposes a lot of internal state).

Screen.Recording.2025-11-09.at.19.52.57.mov

When toggled, the action also tries to cause a recomposition in all the panels so that the bounds do start showing right away, but it doesn't seem to always work/cause a full redraw. Any interaction or change in bounds on the panels will cause the panels to redraw, and that is mostly good enough for now.

Given the approach is reflection-heavy, it is prone to breaking if there are changes in CMP internals; when we have a better, official API for it, we'll be able to have a more robust impl.

CC @igordmn @batya239 @jreznot

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Note

Introduces an internal action that toggles showLayoutBounds for all Compose panels, using reflection, auto-updates on panel attach via AWT listener, and registers the action in resources.

• UI Inspector / Compose:
  • Add ToggleComposeLayoutBoundsAction to toggle showLayoutBounds across active Compose containers; updates presentation text based on state.
  • Implement LayoutBoundsToggler to reflectively set owner.showLayoutBounds, invalidate layers, trigger revalidate/repaint, and listen for AWT HierarchyEvent attachments.
  • Introduce ComposeUtil to locate Compose containers (ComposePanel/ComposeWindow) and traverse to root layout nodes via reflection.
  • Add ReflectHelper for cached reflective field/method access.
• Action Registration / Resources:
  • Register action ToggleComposeLayoutBounds in PlatformActions.xml under internal UI tools.
  • Add action text key action.ToggleComposeLayoutBounds.text to ActionsBundle.properties.

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[rock3r]

Moved to draft since I contributed a better way to enable this in CMP and it will land in CMP 1.11-alpha01.

I will also move this action to the DevKit plugin.