Refactor input interaction routing

[devmobasa]

Summary

Refactors input handling through a new src/input/state/interaction/ routing layer.

• adds typed pointer, keyboard, action, active-interaction, and routing outcome contracts
• moves pointer press/motion/release, keyboard, and action dispatch precedence into explicit router modules
• preserves existing behavior through focused adapters split by pointer, keyboard, action, and active-motion ownership
• adds router-focused tests for modifier keys, right-click cancel/suppression, radial release, properties panel consumption, return-edit miss, idle eraser hover, and action classification