feat(federation): v1.5.0 bump + transport badge on each node card

Every federated node card now shows a colored badge indicating how
archipelago actually reached the peer on the most recent successful
call — FIPS / TOR / LAN / MESH — not a prediction based on available
addresses. The badge is hidden when we've never reached the peer.

Backend:
- Cargo.toml: 1.4.0 → 1.5.0 (visible in the sidebar health endpoint).
- FederatedNode gains last_transport + last_transport_at (serde
  default for back-compat with v1.4 nodes.json files).
- federation::storage::record_peer_transport(did, onion, transport)
  — writes both fields plus last_seen after each successful peer
  call. Matches by DID first, falls back to onion.
- federation::sync::sync_with_peer now calls record_peer_transport
  immediately after a successful PeerRequest return, so the badge
  on the sync'ing peer's card reflects the transport the call
  actually rode (fips vs tor).

Frontend:
- types.ts FederatedNode gains last_transport / last_transport_at
  (union-typed to the four known kinds).
- NodeList.vue: new transportBadge(node) returns {label, cls, title}
  tuned per transport. Hidden when last_transport is absent so we
  never lie. Tooltip shows "Last reached via <x> · <time ago>" so
  stale data is self-evident. Removed the predictive icon from the
  transport store — badge is now 100% ground-truth.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

core/archipelago/src/api/rpc/federation/handlers.rs

@@ -485,6 +485,8 @@ impl RpcHandler {
             last_seen: None,
             last_state: None,
             fips_npub,
+            last_transport: None,
+            last_transport_at: None,
         };
 
         federation::add_node(&self.config.data_dir, node).await?;