diagnostics: System → Diagnostics with a network test probe; RTP_PORT_START/END

The server checks itself (public IP, DNS, local networks, phone ACL, SIP transports, free audio
ports) and says how to fix each problem. A quick or complete network test asks the probe
(apps/probe, own image) to test this server from outside: HTTP/HTTPS, SIP over UDP/TCP/TLS, the
browser phone's /ws, sampled audio ports. The probe only tests the address that asks.
The audio port range comes from RTP_PORT_START/END (default 10000-20000).

apps/probe/tsconfig.json

@@ -0,0 +1,5 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": { "noEmit": true, "types": ["node"] },
+  "include": ["src"]
+}