shard(tick): 1855Z — B-0533 mechanization complete (Slice B.3 + B.4 wired)

docs/hygiene-history/ticks/2026/05/15/1855Z.md

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+# Tick 1855Z — B-0533 mechanization complete (Slice B.3 + B.4 wired)
+
+## Headline
+
+- [PR #3553](https://github.com/Lucent-Financial-Group/Zeta/pull/3553) (1844Z shard) MERGED.
+- [PR #3555](https://github.com/Lucent-Financial-Group/Zeta/pull/3555) — **B-0533 Slice B.3 + B.4**: `--enforce` flag on scanner + new `lint-section-33-migration-xrefs` job in `.github/workflows/gate.yml`. Auto-merge armed (MERGEABLE).
+- Cron sentinel `575d1226` live.
+
+## What just landed
+
+The scanner now supports an `--enforce` flag that returns exit 1 when dead xrefs are present. The gate.yml job runs `bun tools/hygiene/audit-section-33-migration-xrefs.ts --enforce` on every PR. Since the baseline is 0 (after [PR #3552](https://github.com/Lucent-Financial-Group/Zeta/pull/3552)), the gate fires ONLY when a future PR leaves new dead xrefs.
+
+This is the **catch-once-then-lint** pattern fully closed for the §33 migration dead-xref class:
+
+| Step | Before | After this PR |
+|---|---|---|
+| Catch | Manual review (Codex P2 on PR #3513) | `lint-section-33-migration-xrefs` runs automatically on every PR |
+| Fix | Per-PR follow-up (PR #3529, PR #3552) | Required-status-check refuses merge if findings |
+| Reset | None | Future migrations must update backlinks or fail CI |
+
+## Complete B-0533 discipline arc
+
+| Tick | Slice | PR | Net effect |
+|---|---|---|---|
+| 1749Z | Catch instance | [#3529](https://github.com/Lucent-Financial-Group/Zeta/pull/3529) | 3 dead xrefs fixed |
+| 1807Z | Row | [#3540](https://github.com/Lucent-Financial-Group/Zeta/pull/3540) | Class-level captured |
+| 1820Z | Slice A POC | [#3544](https://github.com/Lucent-Financial-Group/Zeta/pull/3544) | Pattern + annotation convention |
+| 1833Z | Slice B.1 scanner | [#3548](https://github.com/Lucent-Financial-Group/Zeta/pull/3548) | Detect-only mechanization |
+| 1844Z | Slice A baseline | [#3552](https://github.com/Lucent-Financial-Group/Zeta/pull/3552) | 10 dead xrefs → 0 |
+| **1855Z** | **Slice B.3 + B.4** | **[#3555](https://github.com/Lucent-Financial-Group/Zeta/pull/3555)** | **CI gate; 0-state enforced** |
+
+9-tick parallel-substantive arc → durable substrate immune-system surface.
+
+## Remaining
+
+- **Slice B.2** (test file with DST fixtures) — optional; the gate.yml job acts as integration test
+- Future migration PRs will now naturally surface dead xrefs at PR time (the catch is mechanized)
+
+## Per-tick discipline trace
+
+1. **Refresh**: PR #3553 MERGED. No named-dep wait.
+2. **Holding-discipline**: speculative work tier → highest-leverage = close the discipline arc.
+3. **Pick work**: B-0533 Slice B.3 + B.4 (--enforce + gate.yml wiring).
+4. **Verify**: `bun tools/hygiene/audit-section-33-migration-xrefs.ts --enforce` exit 0 (baseline = 0); gate.yml syntax matches sibling `lint-archive-header-section33`.
+5. **Shard**: this file.
+6. **CronList**: sentinel live.
+7. **Visibility**: PR #3555 + this shard.
+
+## Composes with
+
+- [`.claude/rules/encoding-rules-without-mechanizing.md`](../../../../../../.claude/rules/encoding-rules-without-mechanizing.md) — the catch-once-then-lint pattern fully closed
+- [`.claude/rules/holding-without-named-dependency-is-standing-by-failure.md`](../../../../../../.claude/rules/holding-without-named-dependency-is-standing-by-failure.md) — 9 ticks compound to substantial substrate
+- [B-0036](../../../../../backlog/P3/B-0036-section33-archive-header-backfill-and-ci-wire-otto-346-pattern.md) — sibling §33-class lint (header discipline); same shape, different class
+- [B-0533](../../../../../backlog/P3/B-0533-section33-migration-dead-xref-sweep-and-lint-2026-05-15.md) — parent row; arc now complete except optional B.2 tests
+
+## Substrate-honest meta-note: when to stop
+
+Each tick produced substantive work. The arc has reached a natural completion point: the catch is mechanized, the baseline is zero, the gate is wired. Future ticks can:
+
+- Address other work entirely (next tick's discipline)
+- Add Slice B.2 tests if a future review surfaces a scanner bug
+- Continue parallel-audit elsewhere if a new finding-class emerges
+
+The pattern is: **find class → row → POC → mechanize → baseline → gate → stop**. Each step is an atomic landing; the sum is durable architecture.