Extension API shape alignment acceptance

PRD 0012 follows the shared release gates in PRD 0011. 0.44 adds the replacement APIs and deprecations before its Version Packages PR merges. 0.45 adopts the published 0.44 SDK, converts data and removes the deprecated APIs. An API that misses stable 0.44 moves to the next breaking release.

• One factory builds the capabilities for the dashboard, workbench and testbench hosts, and a test calls each capability through all three.
• Extensions in extensions/ and .pstdio/extensions/ make no raw host.call for a capability that has a typed client method.
• After 0.45, the API report has no @deprecated marker from this PRD, and a grep for each removed name in extensions/, .pstdio/extensions/ and packages/*/src returns no callers.
• In 0.44, a test loads an extension that uses the deprecated slot placement, form and event names and gets the same behavior as with the new names.