live: AMI-fed live state, /api/live WebSocket, dashboard and status dots

LiveState loads extension states and registered devices from Asterisk on
every AMI connect and follows ExtensionStatus/ContactStatus; the hub sends
a snapshot then deltas batched every 250 ms (devices for admins only),
pings every 30 s and closes unauthenticated sockets with 4401. The web UI
keeps one reconnecting socket in a zustand store, shows a Reconnecting
banner, a Dashboard (online, on a call, telephony engine) and status dots.

Fix: Asterisk 24 has no 'pjsip reload'; reload with
'module reload res_pjsip.so'. AMI errors now carry the CLI output.

Milestone check, automated: call-test.ts registers two baresip phones and
holds a 30 s call with RTP both ways (pnpm test:asterisk); the recorded
session drives the live-state tests. scripts/e2e/m2-live.mjs runs api +
Asterisk + phones + browser on a private Docker network: a new extension
is live in Asterisk in ~1.3 s, the dashboard shows 2/2 online and red dots
during the call.

Task: M2-T6

docs/spec/03-config-generator.md

@@ -76,7 +76,7 @@ All files go to `/etc/asterisk/selfphoneng/`.
 
 | File | Module | AMI `Command:` after change |
 |---|---|---|
-| `pjsip_selfphoneng.conf` | res_pjsip | `pjsip reload` (or restart-required if transports changed) |
+| `pjsip_selfphoneng.conf` | res_pjsip | `module reload res_pjsip.so` (or restart-required if transports changed). Asterisk 24 has no `pjsip reload` CLI command. |
 | `extensions_selfphoneng.conf` | pbx_config | `dialplan reload` |
 | `extensions_globals_selfphoneng.conf` | pbx_config | `dialplan reload` |
 | `voicemail_selfphoneng.conf` | app_voicemail | `voicemail reload` |