feat(mesh): show federated Archipelago nodes on the Mesh Map

Peers that opt in via a new "Share Location" toggle in Settings
(server.set-location RPC) get plotted on other trusted peers' Mesh Map
with a distinct Archy-logo marker, separate from raw LoRa radio peers.
Location is persisted locally, carried in NodeStateSnapshot, and
propagated through federation sync/delta like other node state.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

core/archipelago/src/api/rpc/dispatcher.rs

@@ -419,6 +419,7 @@ impl RpcHandler {
 
             // Server settings
             "server.set-name" => self.handle_server_set_name(params).await,
+            "server.set-location" => self.handle_server_set_location(params).await,
 
             // System monitoring
             "system.get-hostname" => self.handle_system_get_hostname().await,