Merge remote-tracking branch 'origin/master' into gitea/feature/end

Resolved conflicts taking origin/master (v0.5.55) as canonical, with local
features re-applied:
- runtime log level (LOG_LEVEL env + dashboard Settings → Logging, applied
  immediately and persisted across restarts)
- free/noAuth provider enable/disable toggle via providerStrategies.enabled
- parallel model testing (Test All Models / Test Selected Keys)

public/i18n/literals/ro.json

@@ -12,6 +12,7 @@
   "Logout": "Ieșire",
   "Login": "Conectare",
   "Providers": "Furnizori",
+  "Style": "Stil",
   "Usage": "Statistici de utilizare",
   "API Key": "Cheie API",
   "Connected": "Conectat",
@@ -176,6 +177,7 @@
   "How it works:": "Cum funcționează:",
   "Antigravity/Copilot IDE request → DNS redirect to localhost:443 → MITM proxy intercepts → 9Router → response to Antigravity/Copilot": "Solicitare Antigravity/Copilot IDE → Redirecționare DNS la localhost:443 → Proxy MITM interceptează → 9Router → răspuns la Antigravity/Copilot",
   "No API keys — create one in Keys page": "Nicio cheie API — creați una în pagina Chei",
+  "e.g. a warm, gentle voice, speaking slowly with a British accent": "ex.: voce caldă și blândă, vorbind încet cu accent britanic",
   "sk_9router (default)": "sk_9router (implicit)",
   "Server started": "Server pornit",
   "Failed to start server": "Nu s-a putut porni serverul",