Docs/architecture documentation

[YLaxmikanth]

Summary

Improved repository documentation to make onboarding, development, and maintenance easier for contributors.

Changes Made

• Added Architecture Overview to README
• Added Project Structure documentation
• Added Extension Workflow explanation
• Added Browser Compatibility notes
• Added Developer Workflow section to CONTRIBUTING
• Added Troubleshooting guide
• Added Important Files reference for contributors
• Added JSDoc comments to major functions in content.js
• Added JSDoc comments and module documentation to background.js
• Added docs/ARCHITECTURE.md documenting runtime components, message flow, browser compatibility, and build process

These changes improve contributor onboarding and help future maintainers understand the extension architecture without modifying runtime behavior.

Fixes #4

Testing

Documentation-only changes.

Verified:

• Documentation formatting renders correctly
• Markdown links resolve correctly
• New architecture document is referenced from README
• Source code comments do not affect functionality

Checklist

• I have tested the change locally.
• I have updated documentation if needed.

[Labreo]

Good try but please reverse all the changes you have made to the incode documents and the readme. I don't want those changes to be there.

[Labreo]

I don't want there to be anything to be added to the main readme. Please remove those changes.