Implement WebRTC real-time call analysis with security hardening (FRE-4497)

- signaling-server.ts: JWT auth, origin validation, JSON schema validation,
  crypto.randomBytes peer IDs, message size limits, idle timeout, graceful shutdown
- alert-server.ts: JWT auth enabled by default, non-empty jwtSecret from env,
  origin allowlist, per-subscriber callId filtering, bounded alert history with TTL,
  alert cooldown, graceful shutdown with timeout
- call-analysis-engine.ts: Bounded eventBuffer/anomalyBuffer with FIFO eviction,
  real quality metrics from signal properties, configurable buffer sizes
- audio-stream-capture.ts: Proper destroy() lifecycle with awaited stop(),
  AudioWorklet support with ScriptProcessorNode fallback, bounded frame buffers
- Added ws dependency and server tsconfig

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/package-lock.json

@@ -0,0 +1,58 @@
+{
+  "name": "server",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "dependencies": {
+        "@types/ws": "^8.18.1",
+        "ws": "^8.20.0"
+      }
+    },
+    "node_modules/@types/node": {
+      "version": "25.6.0",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-25.6.0.tgz",
+      "integrity": "sha512-+qIYRKdNYJwY3vRCZMdJbPLJAtGjQBudzZzdzwQYkEPQd+PJGixUL5QfvCLDaULoLv+RhT3LDkwEfKaAkgSmNQ==",
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~7.19.0"
+      }
+    },
+    "node_modules/@types/ws": {
+      "version": "8.18.1",
+      "resolved": "https://registry.npmjs.org/@types/ws/-/ws-8.18.1.tgz",
+      "integrity": "sha512-ThVF6DCVhA8kUGy+aazFQ4kXQ7E1Ty7A3ypFOe0IcJV8O/M511G99AW24irKrW56Wt44yG9+ij8FaqoBGkuBXg==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*"
+      }
+    },
+    "node_modules/undici-types": {
+      "version": "7.19.2",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-7.19.2.tgz",
+      "integrity": "sha512-qYVnV5OEm2AW8cJMCpdV20CDyaN3g0AjDlOGf1OW4iaDEx8MwdtChUp4zu4H0VP3nDRF/8RKWH+IPp9uW0YGZg==",
+      "license": "MIT"
+    },
+    "node_modules/ws": {
+      "version": "8.20.0",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.20.0.tgz",
+      "integrity": "sha512-sAt8BhgNbzCtgGbt2OxmpuryO63ZoDk/sqaB/znQm94T4fCEsy/yV+7CdC1kJhOU9lboAEU7R3kquuycDoibVA==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    }
+  }
+}