ivrs: digital receptionist with keypad grid, SoundPicker, golden case

/api/ivrs CRUD: greeting and wrong-key sounds must be prompts, every
option destination must exist (an option may point at its own menu),
keys unique; delete drops the menu's own options before checking
references, inside a transaction so a refused delete keeps them. The
generator renders sp-ivr-{id} per 03 §6.9 (Background greeting,
WaitExten, keys sorted, i/t retry then give up, include sp-local-numbers
for direct dial), adds the number to sp-local-numbers, and destApp sends
ivr destinations there. Golden case ivr (incl. # and self-reference).

Web: Digital receptionist page with a 3x4 keypad grid (pick a key, then
its destination or "unused"), SoundPicker (pick, play, upload new right
in the form), DestinationPicker gains "Digital receptionist" and a shared
target source; useDescribeDestination labels unsaved keys.

e2e m6-t3: menu built in the UI, the greeting plays, keys 1/2 ring the
right phones, a wrong key plays pbx-invalid and repeats the greeting.

Task: M6-T3

apps/api/src/generator/index.ts

@@ -17,6 +17,7 @@ import { renderDids, renderTrunkEntries } from './dialplan/inbound.ts';
 import { renderOutbound } from './dialplan/outbound.ts';
 import { renderEmergency } from './dialplan/emergency.ts';
 import { renderRingGroups } from './dialplan/ringgroups.ts';
+import { renderIvrs } from './dialplan/ivrs.ts';
 import { renderVoicemail } from './voicemail.ts';
 
 export { renderTransports };
@@ -50,6 +51,7 @@ const BODIES: Partial<Record<GeneratedFileName, (snap: Snapshot) => string>> = {
       STATIC_DIALPLAN,
       renderLocalNumbers(snap),
       renderRingGroups(snap),
+      renderIvrs(snap),
       renderTrunkEntries(snap),
       renderDids(snap),
       renderOutbound(snap),