docs: Add FAQ section for common questions

[meichuanyi]

This PR adds a FAQ section to the README.md to help users quickly understand the project and find answers to common questions.

Changes

• Added FAQ section with project overview
• Added Key Features table with 6 points
• Added Installation guide reference
• Added Free and open source policy
• Added Help resources (GitHub Issues/Docs/Discord)
• Added License information

Benefits

• New users can quickly understand what this project does
• Common questions are answered upfront
• Reduces support burden by providing self-help resources

Please review and merge if appropriate. Thank you!

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Summary by cubic

Adds a concise FAQ to the README to help users understand the project, install it, and find support. This should reduce common questions and improve onboarding.

• New Features
  • Project overview and key features table
  • Link to installation instructions
  • Free/open-source note and license details
  • Support links: GitHub Issues, Docs, and Discord

^{Written for commit 9c74c4f. Summary will update on new commits.}