docs(briefs): rollback PB-Substrate pilot worker brief from #772 (premise invalidated)

[briansrls]

Summary

Rolls back the worker brief landed by #772. Premise invalidated by codex BLOCKING finding: the brief targeted CardinalityBound round-trip, but CardinalityBound is already generated from substrate.dag via dag_scalar_generated.rs (included from dag.rs:497). Executing the brief as-written would create a parallel-representation duplication (P2 violation).

Director ruled (#766 escalation thread) for option (c) primary: characterize existing pattern as cascade evidence; optional (a) pilot on uncovered substrate type. Replacement worker brief targeting ArithmeticOp (declared in substrate.dag, hand-authored at dag.rs:694-725, ungenerated) lands separately.

Removing the invalidated brief is cleaner than amending in place — the brief committed to a slice that doesn't exist as hand-authored.

Companion PRs

• docs(audit): cascade evidence reframe — substrate generation already proven (Director-approved per #766 escalation) #775 — audit doc reframe (substrate generation already proven; cascade evidence base shifts).
• Replacement (a) pilot brief (ArithmeticOp) — authored after this + docs(audit): cascade evidence reframe — substrate generation already proven (Director-approved per #766 escalation) #775 land.

Test plan

• Pure deletion. No code surface.

🤖 Generated with Claude Code

[briansrls]

Review metadata

• Provider / model: claude / claude-opus-4-7
• Commit: 608c80fb · Trigger: schedule
• Thinking: 9.9s wall

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Pure documentation rollback — deletes a single brief file, no code change.

Verdict: APPROVE — diff deletes one orphaned brief (docs/briefs/pb-substrate-pilot-worker.md) per the stated rollback rationale. No code, no substrate, no tests touched; nothing in INVARIANTS.md, MODELING.md, CODING.md, or TESTING.md applies. Clean.

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: 608c80fb · Trigger: schedule
• Thinking: 97s wall

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Non-blocking — Strengths

• docs/briefs/pb-substrate-pilot-worker.md Removing the invalidated brief avoids a pilot that would duplicate the existing substrate-generated CardinalityBound authority.

✅ No blocking concerns; this is a clean docs rollback with no added lines to flag.

[briansrls]

Review metadata

• Provider / model: codex / codex-default
• Commit: 608c80fb · Trigger: schedule
• Thinking: 89s wall

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Verdict: APPROVE — This diff only deletes the invalidated PB-Substrate pilot worker brief. I found no concrete violations of the pinned invariants, coding discipline, or testing discipline, and no direct dangling references to the deleted brief.

[briansrls]

Review metadata

• Provider / model: openai-pro / gpt-5-5-pro
• Commit: 608c80fb · Trigger: manual
• Conversation: View conversation

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1. Story of the diff

This PR rolls back the PB-Substrate pilot worker brief by deleting docs/briefs/pb-substrate-pilot-worker.md in full. The removed brief had dispatched a narrow CardinalityBound generation pilot, including build-script generation, a generated enum beside the hand-authored runtime enum, and a cementing test plan (docs/briefs/pb-substrate-pilot-worker.md:40-56). With the premise invalidated, the mechanism here is intentionally subtractive: remove the worker instructions rather than carrying a stale migration scaffold forward. No compiler code, substrate .dag declarations, tests, or design authority files are changed by this diff.

2. Invariant categories

1. LAYER MODEL (substrate vs implementation).

N/A — the diff deletes a Markdown worker brief only; it does not change substrate declarations, dag.rs, cross-pass types, or Dag mutation. The deleted brief referenced substrate/runtime files (docs/briefs/pb-substrate-pilot-worker.md:13-15), but this PR removes those instructions rather than modifying those layers.

1. INVARIANTS.md + modeling-discipline.md.

Compliant — Progress Is Dissolution / tracked-scaffold discipline is honored by removing an invalidated pilot plan instead of preserving it as stale authority. The removed brief explicitly described a temporary additive pilot with a generated counterpart living beside the hand-authored enum (docs/briefs/pb-substrate-pilot-worker.md:46); deleting it avoids normalizing that parallel representation as active work.

1. CODING.md.

N/A — no Rust implementation code, helper placement, method/free-function shape, naming, or error/result surface is touched. The only changed artifact is the deleted brief headed at docs/briefs/pb-substrate-pilot-worker.md:1.

1. TESTING.md.

N/A — no executable behavior changes, so no new unit, integration, boundary, or cementing test is required. The deleted acceptance checklist did include proposed future test obligations (docs/briefs/pb-substrate-pilot-worker.md:52-56), but this PR removes the unexecuted plan rather than landing behavior without coverage.

1. LOCKED DESIGN DECISIONS.

N/A — the deleted brief cited design-pure-bootstrap-zero.md as a proposal-era deliverable (docs/briefs/pb-substrate-pilot-worker.md:3-7) and referenced DB-8 as a gate (docs/briefs/pb-substrate-pilot-worker.md:56), but this diff does not alter the thesis, a locked design doc, DB-8, or any live substrate contract.

1. TRACKED vs UNTRACKED DEBT.

Compliant — no new scaffold, TODO, bridge, or temporary shape is introduced. The removed document was itself a bounded pilot brief with explicit scope controls (docs/briefs/pb-substrate-pilot-worker.md:19-21), non-goals (docs/briefs/pb-substrate-pilot-worker.md:71-75), and stop/escalation triggers (docs/briefs/pb-substrate-pilot-worker.md:59-67); deleting it leaves no new untracked debt in the diff.

3. Verdict

APPROVE

The PR is a clean documentation rollback: it removes an invalidated worker brief and does not mutate substrate, implementation, tests, or locked design surfaces. I did not raise stale-reference or repo-wide linkage concerns because no changed line in this diff shows such a reference.

[briansrls]

PM triage — LAND (rollback still applicable).

Verified: docs/briefs/pb-substrate-pilot-worker.md IS still on main. The rollback PR is still applicable; the brief has not been retired by another path.

This rollback has been pending for 12+ hours (created 2026-04-25T02:59Z; last updated 04:41Z). Per the PR body, premise is sound: codex BLOCKING finding established that the brief targeted CardinalityBound round-trip but CardinalityBound is already generated from substrate.dag via dag_scalar_generated.rs:497 — execution would create P2 parallel-representation duplication.

Replacement worker brief targeting ArithmeticOp (pb-substrate-pilot-v2-arithmeticop.md) is also on main, so the rollback doesn't leave the lane unstaffed — the v2 brief takes its place.

Doc-only diff (-86 lines, retiring the invalidated brief). Cleared to land. Director: please merge or close-with-rationale; pending state is the only abnormal signal here.

[briansrls]

PM review — APPROVE

Clean rollback. -86/+0 deletion of a brief whose premise was invalidated, with the replacement (PB-1-e) already authored and merged separately via #786. This is the right discipline per feedback_redirect_noop_prs — when premise breaks, redirect (replacement brief) rather than ship a no-op; the rollback is the durable receipt that the original is no longer authority.

Ready to merge.