docs: update AGENTS.md to reflect current project state

[heitorrsdev]

Description

Updates the AGENTS.md documentation to accurately reflect the current state of the project architecture, tooling, and workflow. The previous version had become partially outdated as the project evolved, particularly around task execution, authentication, and testing.

What was done

• Updated project overview to include implemented authentication (JWT + refresh tokens)
• Corrected task runner documentation to match the current Taskfile structure
• Replaced obsolete commands (dev-*, ci-test) with the current task workflow
• Updated testing instructions to use task test instead of pnpm test
• Adjusted project structure description to match the current repository layout
• Documented infrastructure components such as JWT authentication, refresh token storage, and structured logging
• Clarified environment configuration via Taskfile dotenv integration
• Improved architectural descriptions to better reflect the implemented layers and responsibilities

Why

AGENTS.md serves as the primary context file for AI agents operating on the repository.
Outdated instructions can lead to incorrect assumptions about project tooling, architecture, and workflows.

Updating this document ensures that automated agents and contributors have an accurate understanding of:

• how the project is structured
• how tasks must be executed
• how authentication and infrastructure components are organized
• how tests and environments are managed

Maintaining accurate agent context is critical to avoid incorrect code changes, misuse of tooling, or architectural violations.