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/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "@selfphoneng/probe",
+  "version": "0.0.2",
+  "private": true,
+  "license": "AGPL-3.0-or-later",
+  "type": "module",
+  "scripts": {
+    "start": "node src/index.ts",
+    "typecheck": "tsc --noEmit"
+  }
+}