voicemail: index messages, live event, email with the recording

services/voicemail.ts rescans a mailbox on Asterisk's MessageWaiting event
(and every mailbox on AMI connect) instead of watching files, upserts
voicemail_messages by msg_id, marks vanished ones deleted, sends
voicemail.new to the owner only, and emails the wav. Delete-after-email
uses AMI VoicemailRemove, and only when the audio was attached. Asterisk
24 has VoicemailMove/VoicemailRemove, so 04 §5.6 drops the renumbering
plan. New VOICEMAIL_DIR setting; e2e m4-t2 checks the email arrives
within 10 s with a playable attachment (SMTP sink shared with m3-t4).

Task: M4-T2

scripts/e2e/README.md

@@ -45,3 +45,9 @@ baresip phones, and `trunk-test.ts` with registration against a fake provider) n
 `m3-t5.mjs` is the M3-T5 acceptance and needs its own fresh database: it signs in with the
 initial password, walks all ten wizard steps against a fake voip.ms, then proves an inbound call
 to the DID rings the new user's softphone and an outbound call leaves with the DID as caller ID.
+
+`m4-t2.mjs` is the M4-T2 acceptance (no browser): start m2-live with a voicemail dir
+(`m2-live.mjs up <confDir> <vmDir>`) and the api with `VOICEMAIL_DIR=<vmDir>`. It runs the SMTP
+sink (`smtp-sink.mjs`, shared with `m3-t4.mjs`), adds a user and extension 150 with voicemail,
+leaves a message from a Local channel, and checks the email arrives within 10 s with a PCM 8 kHz
+wav attached. The voicemail itself (MWI on a phone, `*97`) is covered by `pnpm test:asterisk`.