docs: update README with structured template, contributing guide, and project details

[devin-ai-integration]

Summary

Restructured the README.md to follow a standardized template format with:

• Table of Contents for easy navigation
• Dedicated Description, Installation, and Usage sections
• Contributing guidelines with step-by-step instructions
• Proper License section linking to the Boost Software License 1.0
• Contact section with organization and project links

All existing content (features, tech stack, project structure, architecture, keyboard shortcuts) has been preserved and organized under the new structure.

Review & Testing Checklist for Human

Low risk (documentation-only change):

• Verify all Table of Contents links resolve correctly when rendered on GitHub
• Confirm the project description accurately represents the IDE's capabilities
• Check that installation/usage instructions match the actual development workflow

Notes

This is a documentation-only change — no code was modified. The README now follows a consistent template format shared across all ATC-O48 repositories.

Link to Devin session: https://app.devin.ai/sessions/32a1a59ee8cf441bae60b35d601b34c6

[devin-ai-integration]

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