docs(r3): lane1→lane2 import spec — explicit CI ratchet carrier + join key

docs/briefs/r3-v-lane1-lane2-corpus-identity-import-spec.md

@@ -8,7 +8,7 @@
 
 ## In-repo authority anchors (not PR labels alone)
 
-GitHub PR numbers (**#1393**, **#1394**, **#1412**, …) are **dispatch provenance**, not a substitute for merged design text. This contract’s **in-tree** Markdown links resolve from **`docs/briefs/`** as **`../../…`** for repo-root files (`INVARIANTS.md`, `TESTING.md`, `src/…`) and **`../…`** for other files under `docs/` — a **`../INVARIANTS.md`** link would incorrectly resolve under `docs/` and **does not exist** (common false “missing authority” report). §P1 / §P2 URL fragments (`#p1-modeling-faithfulness`, `#p2-boundary-discipline`) target GitHub’s auto-generated heading anchors for `## P1: Modeling Faithfulness` and `## P2: Boundary Discipline` in [`INVARIANTS.md`](../../INVARIANTS.md). **Same commitments (compact):** list items **1–2** under **[The five principles](../../INVARIANTS.md#the-five-principles)** (“Modeling Faithfulness”, “Boundary Discipline”). **Mechanical live check:** §In-tree anchor verification receipt below (`git cat-file -e origin/main:<path>` on every hyperlinked path).
+GitHub PR numbers (**#1393**, **#1394**, **#1412**, …) are **dispatch provenance**, not a substitute for merged design text. This contract’s **in-tree** Markdown links resolve from **`docs/briefs/`** as **`../../…`** for repo-root files (`INVARIANTS.md`, `TESTING.md`, `src/…`) and **`../…`** for other files under `docs/` — a **`../INVARIANTS.md`** link would incorrectly resolve under `docs/` and **does not exist** (common false “missing authority” report). §P1 / §P2 URL fragments (`#p1-modeling-faithfulness`, `#p2-boundary-discipline`) target GitHub’s auto-generated heading anchors for `## P1: Modeling Faithfulness` and `## P2: Boundary Discipline` in [`INVARIANTS.md`](../../INVARIANTS.md). **Same commitments (compact):** list items **1–2** under **[The five principles](../../INVARIANTS.md#the-five-principles)** (“Modeling Faithfulness”, “Boundary Discipline”). **Mechanical live check:** §receipt below — **(1)** every hyperlinked path exists on `origin/main`; **(2)** each **in-repo `#fragment`** this brief cites still has backing prose on `origin/main` (expected heading line or explicit `<a id="…">`), so anchor drift fails closed instead of passing on path existence alone.
 
 - **[INVARIANTS.md](../../INVARIANTS.md#p2-boundary-discipline) — §P2 Boundary Discipline** — “every fact lives in exactly one authoritative place”; parallel copies are the failure mode import mechanisms must prevent.
 - **[INVARIANTS §P1](../../INVARIANTS.md#p1-modeling-faithfulness) — Modeling Faithfulness** — substrate extensions (`CertifiedProgramText`, widening `TestClaim`, …) route through the §P1 substrate-fact introduction procedure; not ad hoc fixture forks.
@@ -19,9 +19,9 @@ GitHub PR numbers (**#1393**, **#1394**, **#1412**, …) are **dispatch provenan
 - **[ROADMAP.md](../../ROADMAP.md)** — program-level R3 Verification / debt narrative (dispatch context; named gates stay authoritative in [`r3-structure.md`](../r3-structure.md)).
 - **[modeling-discipline.md](../modeling-discipline.md)** — read alongside any future **§P1** carrier that merges `source` + `file_name` into one nominal.
 
-### In-tree anchor verification receipt
+### In-tree link receipt (paths + cited `#fragments`)
 
-Re-run whenever **`main`** moves materially. **Scope:** every repository-relative path hyperlinked from this brief (extend when adding new links).
+Re-run whenever **`main`** moves materially. **Extend both steps** when adding paths or in-repo `#fragments` from this brief.
 
 ```bash
 git fetch origin
@@ -33,11 +33,22 @@ for p in \
   docs/design-cross-target-equivalence.md \
   docs/design-test-infra.md \
   docs/r3-structure.md \
+  docs/r2-closure-ledger.md \
   docs/briefs/r3-v-l5-corpus-readiness-audit.md \
   docs/briefs/r3-v-l4-l7-direct-readiness-audit.md \
   src/v3/compiler/src/test_runner.rs \
   src/v3/std/verification.dag
 do git cat-file -e "origin/main:$p" || exit 1; done
+
+# Every `#fragment` hyperlinked from this brief — expected Markdown headings or explicit IDs on origin/main.
+git show origin/main:INVARIANTS.md | rg -q '^## The five principles$' || exit 1
+git show origin/main:INVARIANTS.md | rg -q '^## P1: Modeling Faithfulness$' || exit 1
+git show origin/main:INVARIANTS.md | rg -q '^## P2: Boundary Discipline$' || exit 1
+git show origin/main:INVARIANTS.md | rg -q '^## P5: Progress Is Dissolution$' || exit 1
+git show origin/main:INVARIANTS.md | rg -q '<a id="db-1"></a>' || exit 1
+git show origin/main:INVARIANTS.md | rg -q '<a id="c-5"></a>' || exit 1
+git show origin/main:docs/briefs/r3-v-l5-corpus-readiness-audit.md | rg -q '^## 4\. Critical-path consumption from Lane 1 \(boundary\)$' || exit 1
+git show origin/main:TESTING.md | rg -q "^### Don't assert on implementation details$" || exit 1
 ```
 
 ---
@@ -57,6 +68,7 @@ do git cat-file -e "origin/main:$p" || exit 1; done
 ## Shared requirements (all mechanisms)
 
 - **Single editable authority** per corpus program row — second copies are either generated or read-only structural imports.
+- **Cross-lane row key (`HEAD`):** **`TestClaim.name`** — surfaced as **`TestClaimValue.claim_name`** after compile ([`test_runner.rs`](../../src/v3/compiler/src/test_runner.rs)) — is the **authoritative join** for pairing Lane 1 vs Lane 2 rows in CI ratchets; **`source` / `file_name`** remain the compiled program identity payload (§Program identity binding).
 - **Program identity** per row is **one binding** projecting to **`TestClaim.source` + `TestClaim.file_name` together** — see §Program identity binding (not two unrelated strings).
 - **CI-visible drift detection** — silent divergence between Lane 1 and Lane 2 rows is unacceptable (ratchet shape varies by mechanism below).
 - **Harness assertion posture** for future integration code: pin **`ClaimResult` / typed outcomes** (`Pass` / `Fail` / `NotYetImplemented(_)`) structurally — today these variants are the Rust **`TestRunner`** carrier in [`src/v3/compiler/src/test_runner.rs`](../../src/v3/compiler/src/test_runner.rs) (`pub enum ClaimResult`, not a separate `.dag` nominal yet); combine with **[INVARIANTS DB-1](../../INVARIANTS.md#db-1)** (typed diagnostic carriers, not ad hoc warning text) and **[C-5](../../INVARIANTS.md#c-5)** (no string-sentinel probing); operational examples in [**TESTING.md**](../../TESTING.md#dont-assert-on-implementation-details) §“Don’t assert on implementation details.”
@@ -76,13 +88,15 @@ do git cat-file -e "origin/main:$p" || exit 1; done
 3. **Concrete binding pattern (research target):**
    - **Pair discipline (mandatory):** One authoring step / one generator emission defines **both** `source` and `file_name`. **Do not** maintain two independently hand-edited `data …: String` declarations for the same row without a freshness ratchet — that is a **parallel-authority** footgun (violates [INVARIANTS §P2](../../INVARIANTS.md#p2-boundary-discipline) intent).
    - **Acceptable at HEAD:** (i) generated `.dag` fragment that sets both `TestClaim` fields from a **single** template input; (ii) compiler-supported structural literal that supplies both strings **atomically** in one declaration; (iii) interim **paired** imports only if CI ratchet below proves **both** fields stay byte-identical across lanes on every change.
-   - Lane 1 fixture (`r3_verification_l4_emit_eval_match.dag` family) and Lane 2 fixture (`r3_verification_l5_corpus.dag` family) each consume the **same projected pair** for a given corpus key.
+   - Lane 1 fixture (`r3_verification_l4_emit_eval_match.dag` family) and Lane 2 fixture (`r3_verification_l5_corpus.dag` family) each consume the **same projected pair** for a given **row identity** — conventionally the substrate **`TestClaim.name`** field (see CI ratchet).
 
 4. **If imports cannot splice into `TestClaim` fields** at lowering time (tooling gap), do **not** fork strings by hand — fall through to mechanism **(b)** or file a **[INVARIANTS §P1](../../INVARIANTS.md#p1-modeling-faithfulness)** substrate extension for a minimal **`CertifiedProgramText`** record type reused by both lanes (single carrier → dual projection at lowering).
 
 ### CI ratchet (byte-level)
 
-- Add a **hermetic integration assertion**: compile Lane 1 claim DAG + Lane 2 claim DAG, extract the two `TestClaimValue` structs for the **same corpus key**, `assert_eq!(l4.source, l5.source)` and `assert_eq!(l4.file_name, l5.file_name)`.  
+- **Live realization shape (`HEAD`):** the Rust harness already projects each compiled `TestClaim` declaration into **[`TestClaimValue`](../../src/v3/compiler/src/test_runner.rs)** (`source`, `file_name`, `claim_name`, …) via **`TestClaimValue::from_declaration`** — not a separate `.dag` nominal, but a **real, typed integration boundary** used today (e.g. [`r3_verification_l4_l7_l5_skeleton_test.rs`](../../src/v3/compiler/tests/integration/r3_verification_l4_l7_l5_skeleton_test.rs)).
+- **Join discipline (explicit boundary):** pairing Lane 1 vs Lane 2 rows uses an agreed **claim identity** — by default the substrate **`name`** string (== `TestClaimValue.claim_name`). There is **no** dedicated `CorpusKey` carrier **at HEAD**; if `name` is not a sufficient join key for a future corpus, introduce one under **[INVARIANTS §P1](../../INVARIANTS.md#p1-modeling-faithfulness)** rather than inventing ad hoc string conventions in fixtures.
+- Add a **hermetic integration assertion**: compile the Lane 1 verification DAG + Lane 2 verification DAG, resolve the two structural `TestClaim` declarations with the **same** `claim_name`, build **`TestClaimValue`** for each, then `assert_eq!(l4.source, l5.source)` and `assert_eq!(l4.file_name, l5.file_name)`.
 - This is the **import-resolution ratchet**: both lanes must resolve to identical bytes even if authored as separate `TestClaim` rows.
 
 ---
@@ -115,13 +129,18 @@ do git cat-file -e "origin/main:$p" || exit 1; done
 
 Use when **(a)** or **(b)** is blocked by a genuine toolchain limitation **and** Director documents the exception.
 
+This hatch is **scaffold-class** relief, not exempt steady-state. **[INVARIANTS §P5 — Progress Is Dissolution](../../INVARIANTS.md#p5-progress-is-dissolution)** applies: scaffolds need explicit dissolution paths — in particular the §P5 *Scaffold without dissolution trigger* shape resolves only when every scaffold lands with a **named dissolution trigger** (a specific, checkable condition that closes it). Director approval that adds only a ledger hook **without** bounded scope **and** such a trigger blesses **untracked bridge debt** and does **not** meet INVARIANTS Dispatch-Discipline for scaffold introductions (paired dispatch: dissolution trigger + adjacent debt visibility).
+
 ### Acceptable patterns
 
 - **Single** programmatic owner (generator or substrate-adjacent template) with **read-only** consumption elsewhere.
-- **Explicit** ledger entry tying the exception to bridge-retirement / P2 posture (no silent carve-outs).
+- **Bounded scope** in the Director record: which lanes, fixtures, row classes, or claim identities the exception covers — **no** open-ended waiver over arbitrary corpus rows.
+- **Named dissolution trigger**: the checkable event that **retires** this exception (e.g. a §P1 substrate carrier lands; mechanism **(a)** / **(b)** becomes implementable and is scheduled). The trigger must be **machine-checkable or audit-checkable** in principle (merge milestone, issue/PR closure criterion, ledger row completion), not prose-only “eventually.”
+- **Explicit ledger entry** tying the exception to bridge-retirement / **§P2** posture — e.g. [`docs/r2-closure-ledger.md`](../r2-closure-ledger.md) row, **ROADMAP** debt bullet, or owning brief §Acceptance naming the same scope + trigger (no silent carve-outs). **Ledger without scope + trigger is insufficient.**
 
 ### Anti-patterns
 
+- Director records that cite “ledger” or bridge posture **only**, omitting **bounded scope** or **dissolution trigger**.
 - Independently edited **duplicate** `TestClaim.source` blobs between Lane 1 and Lane 2 fixtures.
 - **Serialized** copy/paste text with informal “keep in sync” comments but **no** CI equality ratchet.
 - **Locale-sensitive** or **stdout-shaped** comparisons as stand-ins for source equality.