P5.8 §13.8 Anti-entropy shard reconciler - Verification complete

Verified that all acceptance criteria are met:
- Fingerprint → diff → repair pipeline implemented
- TTL interaction for expired documents
- CDC suppression via origin tag
- Mode A scaling with rendezvous-owned shards
- All 9 acceptance tests passing
- Prometheus metrics and alert defined

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Bead-Id: miroir-uhj.8

notes/miroir-uhj.8.md

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+# P5.8 §13.8 Anti-entropy shard reconciler - Verification Summary
+
+## Bead: miroir-uhj.8
+
+### Implementation Status: COMPLETE ✓
+
+The anti-entropy shard reconciler (plan §13.8) is fully implemented and tested.
+
+### Core Components
+
+1. **`crates/miroir-core/src/anti_entropy.rs`** - Core reconciler
+   - `AntiEntropyReconciler` with fingerprint → diff → repair pipeline
+   - `ShardFingerprint` for Merkle tree fingerprints with bucket hashes
+   - `ReplicaDiff` for divergence detection
+   - `RepairAction` and `RepairReason` for repair tracking
+   - TTL interaction: expired documents are deleted from all replicas
+   - Mode A scaling: each pod scans rendezvous-owned shards
+   - Metrics callbacks for Prometheus integration
+
+2. **`crates/miroir-core/src/rebalancer_worker/anti_entropy_worker.rs`** - Background worker
+   - `AntiEntropyWorker` with leader election via advisory lock
+   - `HttpNodeClient` for node communication
+   - Schedule parsing ("every 6h" format)
+   - Leader lease management with renewal
+   - Metrics integration
+
+3. **`crates/miroir-core/src/config/advanced.rs`** - Configuration
+   - `AntiEntropyConfig` with all required fields
+   - Defaults: `enabled: true`, `schedule: "every 6h"`, `auto_repair: true`
+   - `updated_at_field` and `expires_at_field` for TTL interaction
+
+4. **`crates/miroir-proxy/src/routes/documents.rs`** - Write path integration
+   - `_miroir_updated_at` stamping when `anti_entropy.enabled: true`
+   - Reserved field rejection when enabled
+
+5. **`crates/miroir-proxy/src/middleware.rs`** - Prometheus metrics
+   - `miroir_antientropy_shards_scanned_total`
+   - `miroir_antientropy_mismatches_found_total`
+   - `miroir_antientropy_docs_repaired_total`
+   - `miroir_antientropy_last_scan_completed_seconds`
+
+6. **`charts/miroir/templates/miroir-prometheusrule.yaml`** - Alert
+   - `MiroirAntientropyMismatch`: fires when `increase(miroir_antientropy_mismatches_found_total[18h]) > 0`
+   - Corresponds to 3 consecutive passes at default 6h schedule
+
+### Acceptance Criteria Status
+
+- [x] Induce divergence on 1 shard; reconciler detects within `schedule` interval and repairs
+  - Test: `test_acceptance_1_detect_and_repair_divergence` ✓
+
+- [x] Expired-doc test: stale write with older `updated_at` does NOT resurrect
+  - Test: `test_acceptance_2_expired_doc_no_resurrection` ✓
+
+- [x] CDC subscribers do NOT see anti-entropy writes (filtered by `_miroir_origin`)
+  - Test: `test_acceptance_3_cdc_suppression` ✓
+
+- [x] Mode A: 3 pods, each owns ~1/3 of shards; runs exactly once per shard cluster-wide
+  - Test: `test_acceptance_4_mode_a_shard_partitioning` ✓
+
+### Test Results
+
+All 9 tests pass:
+```
+running 9 tests
+test test_acceptance_1_detect_and_repair_divergence ... ok
+test test_acceptance_2_expired_doc_no_resurrection ... ok
+test test_acceptance_3_cdc_suppression ... ok
+test test_acceptance_4_mode_a_shard_partitioning ... ok
+test test_authoritative_doc_selection ... ok
+test test_authoritative_doc_selection_tiebreak ... ok
+test test_bucket_isolation ... ok
+test test_content_hash_excludes_internal_fields ... ok
+test test_metrics_tracking ... ok
+```
+
+### Verification Date
+
+2025-05-23