feat: implement Extensions with real FreeSWITCH directory integration

- extensions table (tenant-scoped, RLS): number, sip_password_enc
  (AES-256-GCM via packages/shared/src/crypto.ts), caller_id, context,
  sofia_profile, codecs, max_registrations
- apps/api/src/extensions: CRUD (POST/GET/GET:id/DELETE), protected by a
  new generic PermissionGuard (@RequirePermission decorator), tenant
  resolved only from the JWT (never trusted from the client)
- SIP password is returned in plaintext only once, in the create response;
  toPublicExtension() explicitly destructures the encrypted field out
  (not a spread) so it can't leak by accident
- b2bcall-fs-config now resolves real directory data: Tenant.telephonyDomain
  -> Extension.number, decrypts the password, builds proper directory XML
  including a dial-string param (missing it caused originate to fail with
  MANDATORY_IE_MISSING instead of the expected USER_NOT_REGISTERED)
- pinned FreeSWITCH's 357737{domain} to a stable value (b2bcall.local) via a
  vars.xml patch in the Dockerfile -- it previously used the container's
  dynamic IP, which could never match a stored telephony_domain
- added HTTP Basic auth between FreeSWITCH and fs-config
  (gateway-credentials, timingSafeEqual comparison) now that the service
  returns real secret data, closing the gap flagged as pending in the XML
  Curl phase instead of leaving it open
- found and fixed: PermissionGuard's constructor-injected Reflector came
  back undefined at runtime under tsx/esbuild (unreliable cross-file
  decorator metadata emission) -- fixed with an explicit @Inject(Reflector);
  worth watching for in future guards/services run via tsx
- verified end-to-end: create extension -> originate user/<ext> reports
  USER_NOT_REGISTERED (found, not registered) -> delete -> back to
  SUBSCRIBER_ABSENT (not found); password never reappears in any GET;
  unauthenticated fs-config requests get 401
- docs/EXTENSIONS.md

infrastructure/freeswitch/Dockerfile

@@ -46,6 +46,15 @@ COPY overrides/autoload_configs/modules.conf.xml /etc/freeswitch/autoload_config
 COPY overrides/autoload_configs/event_socket.conf.xml /etc/freeswitch/autoload_configs/event_socket.conf.xml
 COPY overrides/autoload_configs/acl.conf.xml /etc/freeswitch/autoload_configs/acl.conf.xml
 COPY overrides/autoload_configs/xml_curl.conf.xml /etc/freeswitch/autoload_configs/xml_curl.conf.xml
+
+# Pino $${domain} num valor estavel em vez do IP dinamico do container
+# (vars.xml vanilla usa "domain=$${local_ip_v4}", que muda a cada restart e
+# nunca bateria com Tenant.telephonyDomain). Ver docs/EXTENSIONS.md.
+ARG DEFAULT_SIP_DOMAIN=b2bcall.local
+RUN sed -i "s/data=\"domain=\$\${local_ip_v4}\"/data=\"domain=${DEFAULT_SIP_DOMAIN}\"/" \
+      /etc/freeswitch/vars.xml \
+    && grep -q "domain=${DEFAULT_SIP_DOMAIN}" /etc/freeswitch/vars.xml
+
 COPY entrypoint.sh /usr/local/bin/entrypoint.sh
 RUN chmod +x /usr/local/bin/entrypoint.sh