P2: peers CRUD and aggregated stats

Backend
- api/peers.rs: list/add/remove + aggregate() that derives totals,
  per-state counts, and tx/rx sums in one pass over the peer list
- poller.rs spawns a 3s tokio loop that emits peers://updated and
  stats://updated; cancelled via abort() on stop_daemon
- DELETE peer URL-encodes the endpoint (the path includes ://) with
  a small inline percent-encoder to avoid a url crate dep
- Tauri commands: peers_list, peer_add (with empty-string guard),
  peer_remove, peers_stats

Frontend
- peers store subscribes to the two events and refreshes after
  add/remove for immediate UI feedback
- Peers view renders endpoint, type, color-coded state badge, and
  formatBytes-formatted rx/tx; the four stat cards re-use a
  reusable Stat component
- AddPeerDialog uses radix-vue's Dialog primitive with regex
  validation for tcp:// and quic:// schemes

src-tauri/src/lib.rs

@@ -2,6 +2,7 @@ pub mod api;
 pub mod commands;
 pub mod elevation;
 pub mod error;
+pub mod poller;
 pub mod sidecar;
 pub mod state;
 
@@ -34,6 +35,10 @@ pub fn run() {
             commands::stop_daemon,
             commands::node_info,
             commands::sidecar_logs,
+            commands::peers_list,
+            commands::peer_add,
+            commands::peer_remove,
+            commands::peers_stats,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");