docs(guide/dev): emphasize importance of running full test suite before committing

[KSXGitHub]

This PR updates documentation and AI instruction files to emphasize the critical importance of running the complete test suite before committing any changes, regardless of how trivial they may seem.

Summary

The changes reinforce testing best practices by making it explicit that all types of changes—including documentation edits, comment modifications, and configuration updates—can potentially break formatting, linting, building, tests, or documentation generation across different feature combinations.

Key Changes

• CONTRIBUTING.md: Added important notes highlighting that the full test suite must be run before committing any change, and clarifying how to handle tests that fail with RUSTFLAGS hints
• AI instruction files (.github/copilot-instructions.md, AGENTS.md, CLAUDE.md, template/ai-instructions/shared.md): Updated to include the same testing guidance with emphasis on running the full test suite regardless of change triviality

Notable Details

• Uses GitHub's [!IMPORTANT] and [!NOTE] alert syntax in CONTRIBUTING.md for better visibility
• Consistently updates all AI instruction files to ensure all code generation tools receive the same guidance
• Explicitly mentions that seemingly "safe" changes (docs, comments, config) still require full test validation

https://claude.ai/code/session_01KKiNFj2QH1VCLR2AHyEvN4

[Copilot]

Pull request overview

This PR updates contributor-facing documentation and the repository’s AI instruction files to explicitly require running the full test.sh suite before committing any change, including “trivial” edits, and documents how to respond to test failures that provide RUSTFLAGS skip hints.

Changes:

• Add GitHub alert callouts in CONTRIBUTING.md emphasizing full-suite validation before committing.
• Update the shared AI-instructions template and all generated AI instruction files to include the same “always run full suite” guidance.
• Document the workflow for tests that fail with RUSTFLAGS / --cfg pdu_test_skip_* hints.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
template/ai-instructions/shared.md	Updates the shared instruction fragment to emphasize running the full suite and following RUSTFLAGS skip hints.
CONTRIBUTING.md	Adds [!IMPORTANT] and [!NOTE] callouts reinforcing full-suite testing and the RUSTFLAGS hint workflow.
CLAUDE.md	Mirrors the updated shared testing guidance in the Claude instruction file.
AGENTS.md	Mirrors the updated shared testing guidance in the agents instruction file.
.github/copilot-instructions.md	Mirrors the updated shared testing guidance in the Copilot instruction file.

[github-actions]

Performance Regression Reports

commit: 12886af

There are no regressions.