Add bridge lane health API and config-ready lane UI for Tier A Week 3.

Probe LINK balances on CCIP bridge contracts, expose proof-transfer metadata on bridge status, and render funded/unfunded lane health on /bridge with extended smoke coverage.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/api/track1/bridge_status_data.go

@@ -198,6 +198,12 @@ func (s *Server) BuildBridgeStatusData(ctx context.Context) map[string]interface
 			}
 		}
 	}
+	if laneHealth, proofTransfers := BuildBridgeLaneHealth(ctx); laneHealth != nil {
+		data["bridge_lanes"] = laneHealth
+		if proofTransfers != nil {
+			data["proof_transfers"] = proofTransfers
+		}
+	}
 	if mode, ok := data["mode"].(map[string]interface{}); ok {
 		if relays, ok := data["ccip_relays"].(map[string]interface{}); ok && len(relays) > 0 {
 			var diagnostics *freshness.Diagnostics