Improve Getting Started Documentation

This plan aims to improve dora-rs's getting-started documentation by creating a comprehensive learning system—including written tutorials, video guides, and runnable code examples—that enables new users to complete their first project within 2-3 hours. Leveraging prior contributions to the dora-rs ecosystem and experience producing AI-assisted programming tutorials, the applicant plans to deliver 8 milestones across 12 weeks: basic setup and rerun simulation before midterm (July 10), followed by multimodal model integration, LLM-based action planning, and adora+octos advanced features before the final deadline (August 24). All outputs will be published as open-source documentation and bilingual video tutorials on GitHub, Bilibili, and YouTube.