feat(metrics): add frontend and backend protocol distribution metrics

ts/proxies/smart-proxy/rust-metrics-adapter.ts

@@ -1,4 +1,4 @@
-import type { IMetrics, IBackendMetrics, IProtocolCacheEntry, IThroughputData, IThroughputHistoryPoint } from './models/metrics-types.js';
+import type { IMetrics, IBackendMetrics, IProtocolCacheEntry, IProtocolDistribution, IThroughputData, IThroughputHistoryPoint } from './models/metrics-types.js';
 import type { RustProxyBridge } from './rust-proxy-bridge.js';
 
 /**
@@ -90,6 +90,49 @@ export class RustMetricsAdapter implements IMetrics {
       result.sort((a, b) => b.count - a.count);
       return result.slice(0, limit);
     },
+    frontendProtocols: (): IProtocolDistribution => {
+      const fp = this.cache?.frontendProtocols;
+      return {
+        h1Active: fp?.h1Active ?? 0,
+        h1Total: fp?.h1Total ?? 0,
+        h2Active: fp?.h2Active ?? 0,
+        h2Total: fp?.h2Total ?? 0,
+        h3Active: fp?.h3Active ?? 0,
+        h3Total: fp?.h3Total ?? 0,
+        wsActive: fp?.wsActive ?? 0,
+        wsTotal: fp?.wsTotal ?? 0,
+        otherActive: fp?.otherActive ?? 0,
+        otherTotal: fp?.otherTotal ?? 0,
+      };
+    },
+    backendProtocols: (): IProtocolDistribution => {
+      // Merge per-backend h1/h2/h3 data with aggregate ws/other counters
+      const bp = this.cache?.backendProtocols;
+      let h1Active = 0, h1Total = 0;
+      let h2Active = 0, h2Total = 0;
+      let h3Active = 0, h3Total = 0;
+      if (this.cache?.backends) {
+        for (const bm of Object.values(this.cache.backends)) {
+          const m = bm as any;
+          const active = m.activeConnections ?? 0;
+          const total = m.totalConnections ?? 0;
+          switch (m.protocol) {
+            case 'h2': h2Active += active; h2Total += total; break;
+            case 'h3': h3Active += active; h3Total += total; break;
+            default: h1Active += active; h1Total += total; break;
+          }
+        }
+      }
+      return {
+        h1Active, h1Total,
+        h2Active, h2Total,
+        h3Active, h3Total,
+        wsActive: bp?.wsActive ?? 0,
+        wsTotal: bp?.wsTotal ?? 0,
+        otherActive: bp?.otherActive ?? 0,
+        otherTotal: bp?.otherTotal ?? 0,
+      };
+    },
   };
 
   public throughput = {