Canvas editor component

This component-only package imports the public Canvas, Placement and Placeable interfaces. Its query spans all three; its only write is the named Canvas name setter. It has no process, Worker, database, private action protocol or copy of canonical state. The input draft is ordinary temporary UI state.

The checked artifact builder generates src/gen/client.ts. Editor uses the selected Camino React SDK and declares its styles as a build dependency. Studio supplies the shared session and a subject reference. The package can be replaced independently of the canvas capability implementation or the title-only card.

Normal independent source checkout/scaffold recipes are qualified in WI-12; these resource pins are the source snapshot used by the Studio integration test.