feat(sync): Phase 6 - observability and production readiness

- Add SyncMetrics with full Prometheus integration
- Track sync gaps via catchup events
- Update Grafana dashboard with sync panels
- Document all sync configuration options
- Update design doc with implementation notes

1 files changed, 2 insertions, 0 deletions

diff --git a/src/sync/mod.rs b/src/sync/mod.rs
index dc11812..67d389e 100644
--- a/src/sync/mod.rs
+++ b/src/sync/mod.rs
@@ -21,12 +21,14 @@ mod connection;
 mod filter;
 pub mod health;
 mod manager;
+pub mod metrics;
 pub mod negentropy;
 mod subscription;
 
 pub use filter::FilterService;
 pub use health::{HealthState, RelayHealth, RelayHealthTracker};
 pub use manager::SyncManager;
+pub use metrics::SyncMetrics;
 pub use negentropy::NegentropyService;
 pub use subscription::SubscriptionManager;