This pull request adds a comprehensive AGENTS.md file to the project, providing clear documentation on project structure, workflows, coding conventions, and troubleshooting. This addition will help team members quickly understand how the project is organized and how to contribute effectively.

Project documentation:

• Added AGENTS.md with sections covering project snapshot, quick start, build and verification, and project layout, giving an overview of the development and deployment process.
• Detailed content workflows for notes, posts, images, and metadata, including best practices for structure and accessibility.

Coding standards and conventions:

• Defined conventions for file naming, HTML semantics, classless CSS, JavaScript, accessibility, performance, and security, ensuring consistency across the codebase.

Development and tooling guidance:

• Explained Eleventy helpers, CSS processing, collection configuration, and lifecycle hooks to help contributors extend and maintain the build system.
• Provided troubleshooting steps and Git workflow guidelines, including commit conventions and process documentation expectations.