Decide: sunset flow_* MCP ops or keep them alongside scaffold_*

[stackbilt-admin]

Context

Originally reported by codebeast (via Kurt) as "flow_quality / flow_governance return {hash} echo only" — sibling to Stackbilt-dev/tarotscript#199. That specific bug was an envelope-unwrap issue in the gateway (gateway was reading receipt fields off the root; worker nests them under .receipt.*). Fixed + regression tests added alongside this issue's filing.

This follow-up captures the larger design decision Codebeast raised: given that flow_* is being sunset in favor of scaffold_*, should we delete the flow_* ops from the MCP manifest entirely, or keep them as thin wrappers?

Current state (post-fix)

All five flow_* ops are functional:

• flow_create — async scaffold run, returns receipt hash
• flow_status — {verified, createdAt, hash}
• flow_summary — full envelope
• flow_quality — {governance, quality: {confidence, shadow_density, position_count}, hash}
• flow_governance — same as flow_quality (same backing receipt field)

flow_quality and flow_governance still have overlapping semantics. If we're keeping both, we should probably split the fields cleanly: governance → just {governance, hash}, quality → just {quality, hash}. If we're deleting, that split is wasted work.

Proposed options

1. Delete flow_* from the manifest — callers migrate to scaffold_* (or the forthcoming scaffold_quality / scaffold_governance if they exist / are planned). Cleanest if the sunset is real and near.
2. Keep flow_* as wrappers — but split the quality / governance semantics so they're not clones.
3. Keep flow_* marked deprecated — add a deprecated: true flag to the tool descriptions and a deprecation_target: 'scaffold_*' hint. Gives downstream a migration window.

Acceptance

• Decision recorded (with sunset timeline if applicable)
• Manifest + route-table.ts + tool-registry.ts updated to match
• If keeping: flow_quality and flow_governance no longer return identical payloads
• If deleting: downstream callers (codebeast at minimum, possibly others) given a heads-up before the manifest change lands

Cross-repo context

• Fix for the immediate echo bug: this repo, src/gateway.ts envelope unwrap
• Sibling silent-coercion bug: Stackbilt-dev/tarotscript#199 (fixed)
• Original triage: Stackbilt-dev/stackbilt-engine#23 (closed — wrong repo)