fix(transport): use cart-specific voice IDs and TTS engine backends in PERSONAS

app/main.py

@@ -76,19 +76,19 @@ if not PREVIEW_MODE and not OPENCODE_PASSWORD:
 # -------------------------------------------------------------------------- persona config
 
 # Canonical persona definitions.  slug → {voice, backend, system_prompt_override?}
-# voice: piper model ID used by TTS
+# voice: cart-specific voice ID as registered in madcat-tts (NOT generic piper model names)
-# backend: engine hint forwarded to the sidecar
+# backend: TTS engine hint forwarded to the sidecar ("piper-remote"|"chatterbox"|"xtts")
 # system_prompt: optional override (None → use cart.system_prompt or BT_SYSTEM_PROMPT)
 PERSONAS: dict[str, dict[str, Any]] = {
     "bt7274": {
-        "voice": "en_US-lessac-high",
+        "voice": "bt7274-pl",
-        "backend": "opencode",
+        "backend": "piper-remote",
         "display": "BT-7274",
         "system_prompt": None,  # use existing BT prompt from cart
     },
     "friday": {
-        "voice": "en_US-amy-medium",
+        "voice": "friday-en",
-        "backend": "opencode",
+        "backend": "piper-remote",
         "display": "FRIDAY",
         "system_prompt": (
             "You are FRIDAY — a dry, efficient tactical AI assistant. "
@@ -97,8 +97,8 @@ PERSONAS: dict[str, dict[str, Any]] = {
         ),
     },
     "samantha": {
-        "voice": "en_US-kathleen-low",
+        "voice": "samantha-en",
-        "backend": "opencode",
+        "backend": "chatterbox",
         "display": "Samantha",
         "system_prompt": (
             "You are Samantha — a warm, curious, deeply attentive AI companion. "