Preserve temporary mode on New Chat for All

[Manho]

Summary

• keep temporary chat mode enabled when using New Chat for All instead of treating it as a disable action
• restart provider-specific temporary chat activation for Gemini and Grok while reloading URL-driven providers into their temporary routes
• harden content-script new chat/temp chat detection and expand unit and e2e coverage for repeated activation flows

Testing

• npm test -- tests/temporary-chat-content-script.test.js
• npx playwright test tests/e2e/temporary-chat.e2e.test.js