docs: simplify README to be user-focused

Removed technical details (project structure, development info,
architecture diagrams) and focused on user needs:

- What the tool does (simple description)
- How to install it
- Quick start with common commands
- Interactive mode explanation with keyboard shortcuts
- Common tasks (filtering, conflicts, automation)
- FAQ section for common questions
- Minimal, scannable format

The README is now concise and user-friendly, helping users
get started quickly without overwhelming technical details.

Author: onsails