P2.1: Verify server skeleton implementation - all endpoints present

Verified that all required endpoints from P2.1 are already implemented:
- /health (dispatch-exempt, returns 200 immediately)
- /version (dispatch-exempt, returns Meilisearch version)
- /_miroir/ready (dispatch-exempt, 503 until covering quorum)
- /_miroir/topology (admin-key-gated, plan §10 JSON shape)
- /_miroir/shards (admin-key-gated, shard → node mapping)
- /_miroir/metrics (admin-key-gated Prometheus mirror)

Server infrastructure verified:
- Two listeners: :7700 (main) + :9090 (metrics)
- Config loader: file → env → CLI overlay
- JSON structured logging per plan §10
- SIGTERM graceful shutdown with request draining

All 135 lib tests pass.

notes/miroir-9dj.1.md

@@ -0,0 +1,36 @@
+# P2.1 Server Skeleton - Verification Complete
+
+## Task Requirements
+
+All requirements from P2.1 were already implemented in the codebase:
+
+1. **Config loader**: `MiroirConfig::load()` in main.rs - file → env → CLI overlay ✓
+2. **Tracing**: JSON-to-stdout per plan §10 log format ✓
+3. **Two listeners**: `:7700` (client API) + `:9090` (metrics) ✓
+4. **Signal handlers**: SIGTERM graceful shutdown ✓
+5. **GET /health**: Returns `{"status":"available"}` immediately (health.rs) ✓
+6. **GET /version**: Returns Meilisearch version (version.rs) ✓
+7. **GET /_miroir/ready**: 503 until covering quorum reachable (admin_endpoints.rs) ✓
+8. **GET /_miroir/topology**: Plan §10 JSON shape (admin_endpoints.rs) ✓
+9. **GET /_miroir/shards**: Shard → node mapping (admin_endpoints.rs) ✓
+10. **GET /_miroir/metrics**: Admin-key-gated Prometheus metrics (admin_endpoints.rs) ✓
+
+## Auth Verification
+
+- `/health`, `/version`, `/_miroir/ready` are dispatch-exempt (no auth required)
+- `/_miroir/topology`, `/_miroir/shards`, `/_miroir/metrics` require admin key
+
+## Test Results
+
+- 135 lib tests pass
+- All auth tests pass (68 tests)
+- All middleware tests pass (13 tests)
+- All admin_endpoints tests pass (4 tests)
+
+## Files Modified
+
+No changes needed - all functionality already implemented.
+
+## Note
+
+This bead was a verification task rather than implementation. The codebase already contains all required endpoints and infrastructure.