fix(asterisk): actually install core sounds (en, ulaw 1.6.1)

The install-sounds init container was a stub that left /var/lib/asterisk/sounds/en
empty. Result: every SpeakText fallback path (vm-advopts, vm-goodbye, characters:*,
digits/*, beep, pbx-invalid) resolved to a missing file, Asterisk silently failed
each Playback, zero RTP was produced, and callers heard dead air. This is why
dialing *0 (Settings Menu) or *100 (Debug IVR) "picks up quietly" — there is
literally nothing to stream.

Replaced the stub with alpine:3.20 + curl + tar that downloads the pinned
asterisk-core-sounds-en-ulaw-1.6.1.tar.gz (~10 MB) from downloads.asterisk.org
and unpacks it into the sounds emptyDir. Idempotent — skips download if
vm-goodbye is already present.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/asterisk/deployment.yaml

@@ -25,13 +25,30 @@ spec:
         fsGroup: 0
       initContainers:
         - name: install-sounds
-          image: busybox:latest
+          # Downloads Asterisk core sounds (en, ulaw) into the sounds emptyDir
+          # volume so the base Asterisk image (which ships no sounds) can play
+          # vm-advopts, vm-goodbye, digits/*, characters/*, beep, etc. Skips
+          # the download if the directory already contains sound files —
+          # re-running the pod after a hot image reload reuses the unpack.
+          image: alpine:3.20
           command:
             - sh
             - -c
             - |
-              mkdir -p /sounds/en &&
+              set -eu
-              echo "Leaving /var/lib/asterisk/sounds/en empty until the sound bootstrap lane is fixed."
+              if [ -f /sounds/en/vm-goodbye.ulaw ] || [ -f /sounds/en/vm-goodbye.gsm ]; then
+                echo "Sounds already present — skipping download."
+                exit 0
+              fi
+              echo "Installing curl + tar..."
+              apk add --no-cache curl tar gzip >/dev/null
+              cd /tmp
+              echo "Downloading Asterisk core sounds (en, ulaw) 1.6.1..."
+              curl -fsSLO https://downloads.asterisk.org/pub/telephony/sounds/releases/asterisk-core-sounds-en-ulaw-1.6.1.tar.gz
+              echo "Extracting to /sounds/en ..."
+              mkdir -p /sounds/en
+              tar -xzf asterisk-core-sounds-en-ulaw-1.6.1.tar.gz -C /sounds/en
+              echo "Done — $(ls /sounds/en | wc -l) files installed."
           volumeMounts:
             - name: sounds
               mountPath: /sounds/en