* docs: fix grammatical parallelism and clean up markdown links in README
- Fixed grammatical parallelism in QuickStart ("build" -> "building" and added "are" to "Five options are available").
- Converted raw HTML tags to clean Markdown links in Project Structure.
- Fixed capitalization for "React widget".
* docs(readme): update extensions description in Project Structure
Project Structure: Updated the extensions/ directory description in README.md to accurately reference Chatwoot and the React widget (removing the outdated Discord bot reference per maintainer feedback).Project Structure Links: Converted raw HTML links to clean Markdown link syntax for better maintainability and readability.QuickStart Grammar Fixes: Corrected grammatical parallelism ("build" $\rightarrow$ "building" and added "are" to "Five options are available").
