Rewrite README with CLI + MCP dual setup

- Added CLI as primary quick start (npm install -g unrealcli, ue-cli init)
- Side-by-side comparison table of CLI vs MCP approaches
- Full CLI reference: commands, flags, examples, diagnostics
- Restored MCP setup details: requirements, install script, scope config
- Restored usage examples (conversational prompts for AI assistants)
- Added Supported AI Tools table with status
- Restored Python tool registration for custom commands
- Added expanded troubleshooting (Python import errors, plugin loading)
- Added Releases & Distribution section
- Updated architecture diagram showing both CLI and MCP paths

Author: aadeshrao123