Extract IMouseListener

[Wagner-Laranjeiras]

Extract IMouseListener so MouseTool is not tied to the convenience class

What

• Adds an IMouseListener interface covering all mouse handlers plus decorate. MouseListener now implements it.
• MouseTool and PopupMouseTool now accept IMouseListener[] instead of MouseListener[], including in register/deregister.
• Reuses the existing TYPES.MouseListener token, so current bindings keep working and a second token can't cause double dispatch.
• Fixes a latent bug: .reduce((a, b) => a.concat(b)) threw a TypeError when no mouse listeners were registered. It now has an initial [].

Why

MouseTool depended on the concrete MouseListener class. Listeners could not be written without extending it, and the tool is now consistent with the existing ITouchListener approach.

Compatibility

Non-breaking. MouseListener is unchanged in behaviour and still implements all handlers. Existing subclasses and bindings work as before.

Testing

• New mouse-tool.spec.ts builds real Inversify containers. It covers:
  • dispatch to IMouseListener implementations that don't extend MouseListener
  • register/deregister
  • the empty-listener case
• npm run build, npm run lint (0 errors) and npm test (364 tests) pass.

Closes #478