fix(telephony): chown /shared-tts in initContainer + harden security context

Two follow-ups to the Piper TTS wire-up landed in d3ffad9:

1. Telephony-web runs as uid 1654 (non-root), but the hostPath at
   /tmp/tts-audio is owned by root:root 0755. Pod couldn't write .sln16
   files — every Piper call would succeed at the HTTP layer and then
   fall back to the sound map when File.WriteAllBytesAsync threw
   "Permission denied." Extend the existing fix-data-perms initContainer
   to chown the shared-tts mount too (0755 world-readable, so the
   Asterisk pod — running as a different uid — can still read).

2. Pod security context now explicitly sets runAsNonRoot: true + runAsUser
   1654 + runAsGroup 1654 (cluster policy), matching the pattern used
   by every other FlowerCore service.

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

apps/telephony/telephony.yaml

@@ -118,16 +118,25 @@ spec:
         app: telephony-web
     spec:
       securityContext:
+        runAsNonRoot: true
+        runAsUser: 1654
+        runAsGroup: 1654
         fsGroup: 1654
       nodeSelector:
         kubernetes.io/hostname: rke2-agent1
       initContainers:
         - name: fix-data-perms
           image: busybox:latest
-          command: ["sh", "-c", "chown -R 1654:1654 /data"]
+          # Also chown /shared-tts (hostPath /tmp/tts-audio) so the non-root
+          # app user (uid 1654) can write Piper .sln16 files that Asterisk
+          # reads at /var/lib/asterisk/sounds/tts. World-readable (755) is
+          # fine — Asterisk runs as a different uid in the other pod.
+          command: ["sh", "-c", "chown -R 1654:1654 /data && chown 1654:1654 /shared-tts && chmod 0755 /shared-tts"]
           volumeMounts:
             - name: telephony-data
               mountPath: /data
+            - name: shared-tts
+              mountPath: /shared-tts
       hostNetwork: true
       dnsPolicy: ClusterFirstWithHostNet
       affinity:
@@ -141,6 +150,11 @@ spec:
         - name: telephony-web
           image: localhost/fc-telephony-web:v20260325d
           imagePullPolicy: Never
+          securityContext:
+            readOnlyRootFilesystem: true
+            allowPrivilegeEscalation: false
+            capabilities:
+              drop: [ALL]
           ports:
             - containerPort: 5100
               name: http
@@ -170,6 +184,10 @@ spec:
               readOnly: true
             - name: telephony-data
               mountPath: /data
+            - name: tmp
+              mountPath: /tmp
+            - name: logs
+              mountPath: /app/logs
             # Shared TTS audio — we write Piper .sln16 output here; Asterisk
             # pod reads the same hostPath at /var/lib/asterisk/sounds/tts and
             # plays via `sound:tts/<name>`. Both pods are pinned to rke2-agent1.
@@ -201,6 +219,10 @@ spec:
         - name: telephony-data
           persistentVolumeClaim:
             claimName: telephony-data
+        - name: tmp
+          emptyDir: {}
+        - name: logs
+          emptyDir: {}
         - name: shared-tts
           hostPath:
             path: /tmp/tts-audio