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/nl.json

@@ -12,6 +12,7 @@
   "Logout": "Afmelden",
   "Login": "Aanmelden",
   "Providers": "Providers",
+  "Style": "Stijl",
   "Usage": "Statistieken",
   "API Key": "API-sleutel",
   "Connected": "Verbonden",
@@ -176,6 +177,7 @@
   "How it works:": "Hoe het werkt:",
   "Antigravity/Copilot IDE request → DNS redirect to localhost:443 → MITM proxy intercepts → 9Router → response to Antigravity/Copilot": "Antigravity/Copilot IDE-aanvraag → DNS-omleiding naar localhost:443 → MITM-proxy onderschept → 9Router → antwoord naar Antigravity/Copilot",
   "No API keys — create one in Keys page": "Geen API-sleutels — maak er één aan op de pagina Sleutels",
+  "e.g. a warm, gentle voice, speaking slowly with a British accent": "bijv.: een warme, zachte stem, die langzaam praat met een Brits accent",
   "sk_9router (default)": "sk_9router (standaard)",
   "Server started": "Server gestart",
   "Failed to start server": "Server starten mislukt",