docs: move .github/copilot-instructions.md to AGENTS.md

[Copilot]

This change moves the existing .github/copilot-instructions.md file to AGENTS.md in the repository root to follow GitHub's recommended standard for agent instruction files.

Background

GitHub has established AGENTS.md as the standard location for agent instructions that can be used by various AI coding assistants, not just GitHub Copilot. This provides better discoverability and compatibility across different agent platforms.

Changes

• Moved .github/copilot-instructions.md to AGENTS.md
• All content preserved exactly (172 lines of comprehensive development guidelines)
• No functional changes to the codebase

Benefits

• Standards Compliance: Follows GitHub's recommended convention for agent instructions
• Broader Compatibility: Accessible to various AI agents beyond just GitHub Copilot
• Improved Discoverability: Located in repository root for easier access
• Future-Proof: Aligns with evolving standards for AI agent integration

The development guide continues to provide the same comprehensive information about DPDispatcher's build system, testing procedures, project structure, and development workflows.

Fixes #549.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• 39.106.xx.xx
  • Triggering command: python -m coverage run -p --source=./dpdispatcher -m unittest -v (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 47.60%. Comparing base (e92a4f8) to head (8605f6f).
⚠️ Report is 1 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (e92a4f8) and HEAD (8605f6f). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (e92a4f8)	HEAD (8605f6f)
	15	14

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #550       +/-   ##
===========================================
- Coverage   60.40%   47.60%   -12.81%     
===========================================
  Files          39       39               
  Lines        3905     3905               
===========================================
- Hits         2359     1859      -500     
- Misses       1546     2046      +500     

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