Add status page enhancements with new metrics and footer

- Add GC statistics (run count, total/last pause, heap usage)
- Add BGP peer count tracking from RIS Live OPEN/NOTIFICATION messages
- Add route churn rate metric (announcements + withdrawals per second)
- Add announcement and withdrawal counters
- Add footer with attribution, license, and git revision
- Embed git revision at build time via ldflags
- Update HTML template to display all new metrics

internal/streamer/streamer.go

@@ -114,6 +114,8 @@ type Streamer struct {
 	metrics      *metrics.Tracker
 	totalDropped uint64     // Total dropped messages across all handlers
 	random       *rand.Rand // Random number generator for backpressure drops
+	bgpPeers     map[string]bool // Track active BGP peers by peer IP
+	bgpPeersMu   sync.RWMutex    // Protects bgpPeers map
 }
 
 // New creates a new Streamer instance configured to connect to the RIS Live API.
@@ -132,7 +134,8 @@ func New(logger *logger.Logger, metrics *metrics.Tracker) *Streamer {
 		handlers: make([]*handlerInfo, 0),
 		metrics:  metrics,
 		//nolint:gosec // Non-cryptographic randomness is fine for backpressure
-		random: rand.New(rand.NewSource(time.Now().UnixNano())),
+		random:   rand.New(rand.NewSource(time.Now().UnixNano())),
+		bgpPeers: make(map[string]bool),
 	}
 }
 
@@ -608,18 +611,32 @@ func (s *Streamer) stream(ctx context.Context) error {
 			// BGP keepalive messages - silently process
 			continue
 		case "OPEN":
-			// BGP open messages
+			// BGP open messages - track peer as active
+			s.bgpPeersMu.Lock()
+			s.bgpPeers[msg.Peer] = true
+			peerCount := len(s.bgpPeers)
+			s.bgpPeersMu.Unlock()
+			s.metrics.SetBGPPeerCount(peerCount)
+
 			s.logger.Info("BGP session opened",
 				"peer", msg.Peer,
 				"peer_asn", msg.PeerASN,
+				"total_peers", peerCount,
 			)
 
 			continue
 		case "NOTIFICATION":
-			// BGP notification messages (errors)
+			// BGP notification messages (session closed)
+			s.bgpPeersMu.Lock()
+			delete(s.bgpPeers, msg.Peer)
+			peerCount := len(s.bgpPeers)
+			s.bgpPeersMu.Unlock()
+			s.metrics.SetBGPPeerCount(peerCount)
+
 			s.logger.Warn("BGP notification",
 				"peer", msg.Peer,
 				"peer_asn", msg.PeerASN,
+				"total_peers", peerCount,
 			)
 
 			continue