Canvas gestures and hit-testing

Every touch on a hand-drawn canvas (a progress grid, a planner, a chart, a game board) goes through one gesture module, useCanvasGestures, which hit-tests against the same CanvasLayout the renderer draws with and emits at most one typed CanvasIntent per gesture; the surface's pure intentToAction(state, intent) alone decides whether it becomes a domain action. This skill ships that input kit (src/canvas/gestures/), the shape of each surface's intent function and hit-targets test, and a checker that proves both.

Rules that must hold