Add AI agent guidelines and update code style standards

[Copilot]

Adds contributor documentation for AI coding agents and updates project code style configuration.

Added

• AGENTS.md: Comprehensive guidelines for AI agents working on panoptes-utils

  • Project structure and module organization
  • Development workflow and testing requirements
  • Module-specific guidelines (config server, CLI, images, time utilities, serial)
  • Code standards, error handling, and logging patterns
  • Quick reference for common commands
  • Follows pattern established in POCS repository

• CHANGELOG requirement: Explicit guideline to update CHANGELOG.md for all PRs

  • Documented in "Making Changes" section with format examples
  • Listed as required item in "Documentation Updates"

Changed

• Line length: 100 → 110 characters

  • Updated pyproject.toml Ruff configuration
  • Updated AGENTS.md documentation

• CHANGELOG.md: Added "Unreleased" section documenting these changes

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.11%. Comparing base (d64b116) to head (c88b010).
⚠️ Report is 6 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #331   +/-   ##
========================================
  Coverage    85.11%   85.11%           
========================================
  Files           21       21           
  Lines         1344     1344           
========================================
  Hits          1144     1144           
  Misses         200      200           

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[wtgee]

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