v1: landscape / rotation support

[gorlix]

Context

v1 assumes portrait orientation. computeLassoRect maps tap→page using pageH. Landscape and split-page modes change how screen pixels map to page pixels.

Current behavior

Validated only in portrait (A5X2 1920×2560). Landscape / split-page untested and likely mis-maps the cut line.

Goal

Correct behavior in landscape (and ideally split-page), so the cut line and lasso rect land where the user taps regardless of orientation.

Approach

• Read orientation: NativePluginManager.getOrientation() on mount, DeviceEventEmitter('plugin_event_rotation'), and Dimensions.addEventListener('change') (all three per SKILL.md gotcha v1: layer scope toggle (all layers ↔ current layer) #17).
• Adjust the tap→page mapping for the active orientation; consider PointUtils rotation constants.
• Re-validate on device in each orientation.

Acceptance criteria

• Tap maps correctly in portrait and landscape (logcat-verified rect).
• Graceful behavior (or documented unsupported) for split-page.

References

• SKILL.md gotcha v1: layer scope toggle (all layers ↔ current layer) #17, references/floating-window.md
• references/make-space.md §2