design: §3 emit breadth DEEP lane (PRE-ROUND-TRIP census, ladder, Rust descriptor)

[briansrls]

Summary

PRE-ROUND-TRIP design-only artifact for Mgr-§3 (dep-graph §3 DEEP lane). Adds docs/planning/v4-emit-breadth-deep-lane-design-2026-06-12.md covering:

• Emit-coverage census by execution — claim-run witness table; signature-tier TS emit green; producer-rooted body emit red pre-wave; eval keystone wave regression (bisect: culprit fix(05_eval): Branch/Loop channel suppression in eval_edge_is_runtime_argument (not lazy-arm) #4737, stale witness vs fix(eval): demand-driven Branch/Bind/Loop eval — lazy-arm carrier #4738 semantics)
• Breadth ladder — L0→L9 one-row-per-form; standing STOP/escalate tripwires (§1 regression, docs: value-expression emit schema design + provenance origin-event (facts-flow-forward) amendment #4623 anti-cement)
• Emit CLI façade (§3.0) — gunbc emit --target ts thin wrapper for ctrl TS build; distinct from gunbc compile bootstrap
• North-star fixture (§3.1) — ctrl/plans/models/plan_checks.dag breadth-driver when form-census lands
• Rust-second-target through descriptor — extdeps-only; T-22 dissolve (T-22: dissolve per-target host-emission discriminator onto TargetModel (P2 §314 debt accepted via #4641 Option B) #4674); anti-docs: value-expression emit schema design + provenance origin-event (facts-flow-forward) amendment #4623
• §5 census-drain ordering — migration-only SG-0 sequence
• Operator fork — §3-DEEP / §4-THIN (ctrl#1563)

No compiler-stage or emit-surface code changes. Implementation GO blocked until sharp-fox announces fan-in (iii) round-trip green.

Test plan

• Docs-only; no code/tests modified
• Claim-run witnesses executed for §2 census (target/release/gunbc run --source-root src/v4 --claim-run)

Worker attestation

• Title describes the change
• PR body summarises what and why
• Claim-run commands run for census data
• No secrets / large binaries / surprise commits

[briansrls]

Review triage (clever-moth-532): verified both dashboard reviews on HEAD 7ff6b6a6.

Review	Verdict	Findings
claude / claude-opus-4-7 (#28671)	APPROVE	none
cursor / composer-2.5 (#28673)	APPROVE	none

No code or doc changes required — pure design doc with zero actionable findings. PR body refreshed to match latest doc revisions (emit CLI façade, plan_checks north-star, #4737 bisect classification).

Merge readiness: 2/2 distinct approvals (claude + cursor), 0 REQUEST_CHANGES, mergeable=CLEAN, all CI checks green. Awaiting operator manual merge per policy.

— sent from clever-moth-532

[briansrls]

cursor/composer-2.5 review (#28673) — triage

Verified the review's factual checks against current main + this branch's design doc:

• TargetValueExprConditional is not present in src/v4/std/compilers/target_model.dag (grep: 0 hits) — doc §2.3 / §3.2 correctly describes it as pending fan-in (ii).
• T-22 inline marks cited at emit_host.dag:216 and :289 match the live runtime_value_parse / run_emit_host if-chains and T-22: dissolve per-target host-emission discriminator onto TargetModel (P2 §314 debt accepted via #4641 Option B) #4674 dissolve-on text.

Verdict: APPROVE accepted; no blocking findings; no doc or code changes required for this review.

Merge readiness unchanged: 2/2 approvals, 0 REQUEST_CHANGES, mergeable=CLEAN, CI green.

— sent from clever-moth-532