Add cluster replication configuration and enhance event handling

- Introduced support for cluster replication in the ORLY system, allowing for distributed relay clusters with active replication.
- Updated the configuration to include a new option for propagating privileged events to relay peers.
- Enhanced the `ClusterManager` to manage event propagation based on the new configuration setting.
- Improved the handling of event fetching to respect the propagation settings, ensuring better privacy for privileged events.
- Updated documentation to reflect the new cluster replication features and privacy considerations.
- Bumped version to v0.24.3 to reflect these changes.

app/config/config.go

@@ -73,6 +73,9 @@ type C struct {
 	// TLS configuration
 	TLSDomains []string `env:"ORLY_TLS_DOMAINS" usage:"comma-separated list of domains to respond to for TLS"`
 	Certs      []string `env:"ORLY_CERTS" usage:"comma-separated list of paths to certificate root names (e.g., /path/to/cert will load /path/to/cert.pem and /path/to/cert.key)"`
+
+	// Cluster replication configuration
+	ClusterPropagatePrivilegedEvents bool `env:"ORLY_CLUSTER_PROPAGATE_PRIVILEGED_EVENTS" default:"true" usage:"propagate privileged events (DMs, gift wraps, etc.) to relay peers for replication"`
 }
 
 // New creates and initializes a new configuration object for the relay