[Feature] Live Polling System

[mirmousaviii]

Add a live voting feature so the audience can vote via QR code and see real-time results.

• Generate a QR code linking to the poll page.
• Allow multiple choice or yes/no questions.
• Show live results (chart or percentage) on the slide.
• Sync updates instantly during presentation.

Blocked by

• [Feature] Add Speaker Mode #1
• [Feature] QR Code for Slides #2