[Docs] Add AGENTS.md with Sistent design guidance

Current State

The layer5io/recognition repository does not currently have an AGENTS.md file.
The repository consumes @sistent/sistent@0.15.12, but there is no contributor or AI-agent guidance directing UI-related work to the Sistent design contract.

Desired State

Create a lightweight root-level AGENTS.md documenting basic runbook setup and providing a version-accurate reference to Sistent for UI components.

Guidance Requirements

• Version Parity: Because the repository is pinned to @sistent/sistent@0.15.12, direct contributors and AI coding agents to read node_modules/@sistent/sistent/DESIGN.md (or link to the matching release tag: https://github.com/layer5io/sistent/tree/v0.15.12/DESIGN.md) rather than master, preventing guidance drift against newer Sistent versions.
• Single Source of Truth: Instruct agents to consult Sistent's design tokens and conventions before introducing or modifying Sistent-based UI components.
• Avoid Duplication: Do not copy or create a separate DESIGN.md in this repository.

Scope

• Create a concise AGENTS.md at the repository root.
• Include essential project setup/runbook steps.
• Add the Sistent UI contract pointer under UI guidelines.
• Keep the file compact and focused.

Contributor Guides and Resources

• 📚 Instructions for contributing to documentation
  • Meshery documentation site and source
• 🛠 Meshery Build & Release Strategy
• 🎨 Wireframes and designs for Layer5 site in Figma (open invite)
• 🙋🏾🙋🏼 Questions: Layer5 Discussion Forum and Layer5 Community Slack