#1614 docs: improve README for better discoverability

Summary

Significant README improvements for better GitHub discoverability and user onboarding:

• Visual scannability: Added emoji icons throughout (🎵 🛡️ 🌐 📊 🔧 etc.)
• Better structure: Reorganized features into clear categories with icons
• Enhanced Quick Start: Clearer prerequisites, Docker setup, and configuration
• Command reference: Visual tables organized by category (Music, Moderation, Engagement)
• New sections: Tech Stack, Key Stats, Why Self-Host comparison
• Improved copy: More compelling descriptions, better technical clarity
• Visual hierarchy: Better use of headers, tables, and formatting

No feature or functionality changes — this is purely documentation/presentation improvement.

Checklist

• All existing content preserved
• No features added or modified
• Clear visual structure and emoji icons
• Tested link formatting in Markdown

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Summary by cubic

Revamped README to improve GitHub discoverability and onboarding. Documentation only; no functional changes.

• Refactors
  • Restructured features into clear categories with icons for faster scanning.
  • Expanded Quick Start with prerequisites, Docker compose steps, and env setup.
  • Added command reference tables and a concise tech stack overview.
  • Clarified Admin panel setup and streamlined documentation links and copy.

Summary by CodeRabbit

• Documentation
  • Reworked the README with clearer sections, updated branding, and improved links.
  • Expanded feature descriptions into detailed category breakdowns for easier discovery.
  • Added more thorough setup guidance, including prerequisites, Docker, local development, and configuration steps.
  • Reorganized command references into clearer tables with descriptions.
  • Improved development, documentation, contributing, and maintenance guidance with more structured instructions.