feat(tts): add Xiaomi MiMo text-to-speech support

Adds mimo-v2.5-tts as a Media Provider TTS through the existing
OpenAI-compatible chat-completions endpoint. Voice is selected via the
top-level audio.voice field, and an optional style/language hint is
threaded through tts.js -> ttsCore.js -> the new adapter.

public/i18n/literals/es.json

@@ -12,6 +12,7 @@
   "Logout": "Cerrar sesión",
   "Login": "Iniciar sesión",
   "Providers": "Proveedores",
+  "Style": "Estilo",
   "Usage": "Estadísticas",
   "API Key": "Clave API",
   "Connected": "Conectado",
@@ -176,6 +177,7 @@
   "How it works:": "Cómo funciona:",
   "Antigravity/Copilot IDE request → DNS redirect to localhost:443 → MITM proxy intercepts → 9Router → response to Antigravity/Copilot": "Solicitud de Antigravity/Copilot IDE → Redireccionamiento DNS a localhost:443 → El proxy MITM intercepta → 9Router → respuesta a Antigravity/Copilot",
   "No API keys — create one in Keys page": "Sin claves API — cree una en la página Claves",
+  "e.g. a warm, gentle voice, speaking slowly with a British accent": "p. ej.: voz cálida y suave, hablando lentamente con acento británico",
   "sk_9router (default)": "sk_9router (predeterminado)",
   "Server started": "Servidor iniciado",
   "Failed to start server": "Error al iniciar el servidor",