feat(cursor): export skill injection helper and document auto-behaviors

Export ensureCursorSkillsInjected from the server entrypoint and add
a test for skill directory injection. Document the auto-inject and
auto-trust behaviors in the adapter notes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/adapters/cursor-local/src/server/index.ts

@@ -1,4 +1,4 @@
-export { execute } from "./execute.js";
+export { execute, ensureCursorSkillsInjected } from "./execute.js";
 export { testEnvironment } from "./test.js";
 export { parseCursorJsonl, isCursorUnknownSessionError } from "./parse.js";
 import type { AdapterSessionCodec } from "@paperclipai/adapter-utils";