Forward Cursor's file-read hooks so a Guardian can govern file reads #212

The Cursor reference adapter does not forward Cursor's file-read hooks, so file reads an agent makes in Cursor never reach a Guardian and cannot be denied. Cursor's read hooks are blockable upstream, so the gap is in the adapter, not the host.

Done when the Cursor adapter forwards read hooks as ACS hook calls, a Guardian DENY blocks the read, and the adapter's conformance tests cover an allowed and a denied read.

The adapters land through PR #22. This gap is listed in the Strategic Adoption Plan v3 as a deliverable for the AGT interoperability benchmark.