feat(monitoring): add backend protocol metrics to network stats and ops dashboard

ts_interfaces/data/stats.ts

@@ -165,6 +165,7 @@ export interface INetworkMetrics {
   throughputHistory?: Array<{ timestamp: number; in: number; out: number }>;
   requestsPerSecond?: number;
   requestsTotal?: number;
+  backends?: IBackendInfo[];
 }
 
 export interface IConnectionDetails {
@@ -174,4 +175,26 @@ export interface IConnectionDetails {
   startTime: number;
   bytesIn: number;
   bytesOut: number;
+}
+
+export interface IBackendInfo {
+  backend: string;
+  domain: string | null;
+  protocol: string;
+  activeConnections: number;
+  totalConnections: number;
+  connectErrors: number;
+  handshakeErrors: number;
+  requestErrors: number;
+  avgConnectTimeMs: number;
+  poolHitRate: number;
+  h2Failures: number;
+  h2Suppressed: boolean;
+  h3Suppressed: boolean;
+  h2CooldownRemainingSecs: number | null;
+  h3CooldownRemainingSecs: number | null;
+  h2ConsecutiveFailures: number | null;
+  h3ConsecutiveFailures: number | null;
+  h3Port: number | null;
+  cacheAgeSecs: number | null;
 }