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/tl.json

@@ -12,6 +12,7 @@
   "Logout": "Maglog out",
   "Login": "Magsimula ng sesyon",
   "Providers": "Mga Provider",
+  "Style": "Estilo",
   "Usage": "Mga Istatistika ng Paggamit",
   "API Key": "Susi ng API",
   "Connected": "Konektado",
@@ -176,6 +177,7 @@
   "How it works:": "Paano ito gumagana:",
   "Antigravity/Copilot IDE request → DNS redirect to localhost:443 → MITM proxy intercepts → 9Router → response to Antigravity/Copilot": "Antigravity/Copilot IDE request → DNS redirect sa localhost:443 → MITM proxy intercepts → 9Router → response sa Antigravity/Copilot",
   "No API keys — create one in Keys page": "Walang API keys — lumikha ng isa sa Keys page",
+  "e.g. a warm, gentle voice, speaking slowly with a British accent": "hal.: mainit at malumanay na boses, dahan-dahang nagsasalita nang may British accent",
   "sk_9router (default)": "sk_9router (default)",
   "Server started": "Ang server ay nagsimula",
   "Failed to start server": "Nabigo na magsimula ang server",