Adds an optional, fenced Research projection check to channel commits. Both memory and PostgreSQL adapters validate the request, initial turn, and linked job before accepting a document reference change; the storage layer also records Planner inline-reference placement for recovery. Plan/browser wiring follows in a later PR.

A review fix makes the memory adapter check every projection and commit in one synchronous turn. The new race test fails on the old adapter and passes with the fix, so a linked job cannot become terminal between checks.

**Review scope:** 19 files. **Validation:** 59 memory contract tests, full workspace/E2E types, and repository CI pass locally. The PostgreSQL adapter had 67 passing tests on the original layer; All three required GitHub checks pass on the rebased head.


### Review fix: atomic memory projection checks