feat: add Event Socket integration (b2bcall-fs-events)

- packages/telephony: TelephonyProvider interface (agente.md secao 25) and
  FreeSwitchTelephonyProvider implementation over the 'esl' library
  (actively maintained, TypeScript-native, built-in reconnect-with-backoff
  satisfying secao 195); normalizeEslEvent() translates raw ESL events into
  the internal vocabulary (secao 24)
- apps/freeswitch-events (b2bcall-fs-events): permanent ESL connection,
  resubscribes on every reconnect, publishes normalized events to the
  'b2bcall:events' Redis pub/sub channel; containerized (Dockerfile +
  docker-compose service) since its whole job is reaching the freeswitch
  container by internal hostname
- packages/shared: reusable createLogger() (structured JSON per secao 189),
  fixed a BigInt serialization crash surfaced by the esl library's error
  stats
- found and fixed a real FreeSWITCH 1.11 default: without an explicit
  apply-inbound-acl, mod_event_socket silently rejects any non-loopback
  connection ('Access Denied, go away.') even with the correct password —
  added a dedicated ACL (loopback + the Docker Compose network range, never
  0.0.0.0/0) in infrastructure/freeswitch/overrides/autoload_configs/
- verified end-to-end with a local loopback test call: CALL_CREATED ->
  CALL_ANSWERED -> CALL_ENDED observed on the Redis channel with the
  correct callUuid and hangup cause
- docs/EVENT_SOCKET.md

apps/freeswitch-events/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "@b2bcall/freeswitch-events",
+  "version": "0.0.1",
+  "private": true,
+  "scripts": {
+    "dev": "tsx watch src/main.ts",
+    "build": "tsc -p tsconfig.json",
+    "start": "node dist/main.js",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@b2bcall/shared": "workspace:*",
+    "@b2bcall/telephony": "workspace:*",
+    "esl": "11.2.1",
+    "ioredis": "^6.0.0"
+  },
+  "devDependencies": {
+    "@types/node": "^22.0.0",
+    "tsx": "^4.23.12",
+    "typescript": "^5.7.0"
+  }
+}