Hack Day: Legend Contract Conformance Gate in Pipeline

## Summary
Add Legend-based governance checks in generation/CI so service contracts and state artifacts are validated against the canonical semantic model.

## Jump-Off State(s)
- `012-platform-convergence-c3`

## Graph Intent
`canonical candidate`

## Scope
- Add model conformance validation step(s) to pipeline.
- Report breaking/non-conforming deltas with actionable output.
- Define exception/waiver workflow for transitional states.

## Acceptance Criteria
- CI surfaces model conformance status per state.
- Contract drift from canonical model is detected automatically.
- Docs describe governance and remediation workflow.

## Decision Gate (Promote/Park)
Promote if conformance gates improve quality without blocking practical iteration.

Start by locating the generation and CI entry points that process the 012-platform-convergence-c3 state and identify how service contracts and state artifacts are represented. Done means CI reports conformance per state, detects canonical-model drift with actionable output, and documents an exception or waiver workflow.

Written by the indexing model from the issue text.