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

[Copilot]

This PR moves the AI agent instructions from .github/copilot-instructions.md to AGENTS.md in the repository root, following the new GitHub standard for agent custom instructions.

Background

According to the GitHub changelog, AGENTS.md is now the commonly used location for custom instructions that different AI agents can reference. This change improves compatibility across various AI coding assistants.

Changes

• Moved .github/copilot-instructions.md → AGENTS.md
• No content changes - the comprehensive dpdata development instructions remain identical
• No functional impact on the dpdata codebase or CLI functionality

The file contains detailed instructions for AI agents working on dpdata, including:

• Repository bootstrap and installation procedures
• Testing and linting workflows
• Build and documentation processes
• Troubleshooting guides
• Commit and PR guidelines

Verification

• ✅ dpdata CLI functionality remains intact (dpdata --version, dpdata --help)
• ✅ All CLI tests continue to pass (7/7 tests successful)
• ✅ File content preserved exactly (149 lines, 7,357 bytes)

Fixes #897.

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[njzjz]

pre-commit.ci autofix

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.06%. Comparing base (a89a7a4) to head (e9b1e91).
⚠️ Report is 20 commits behind head on devel.

Additional details and impacted files

@@           Coverage Diff           @@
##            devel     #898   +/-   ##
=======================================
  Coverage   86.06%   86.06%           
=======================================
  Files          83       83           
  Lines        7886     7886           
=======================================
  Hits         6787     6787           
  Misses       1099     1099           

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[codspeed-hq]

CodSpeed WallTime Performance Report

Merging #898 will not alter performance

_{Comparing copilot/fix-897 (e9b1e91) with devel (a89a7a4)}

Summary

✅ 2 untouched