chore: developer experience - pre-commit hook, ai instructions, yaml formatting

[jonstelly]

Some minor developer experience items:

• pre-commit hook to run cargo fmt, clippy, test
• README.md addition for registering the git hook
• editorconfig for formatting, mainly for toml, yaml, but tried to replicate rustfmt.toml reasonably
• AGENTS.md - copilot instructions/help for the repository, aiming to constrain/focus copilot a bit, give a bit of context of terminology, code-base

[Copilot]

Pull request overview

This PR enhances developer experience by adding tooling and documentation to support consistent code quality and provide guidance for AI-assisted development. The changes introduce a pre-commit hook for automated quality checks, an editorconfig for consistent formatting across file types, and comprehensive agent instructions for GitHub Copilot.

Changes:

• Added pre-commit hook script that runs formatting, linting, and tests before commits
• Created AGENTS.md with architecture overview, terminology, conventions, and workflow guidance for AI assistants
• Added .editorconfig for consistent editor settings across Rust, YAML, TOML, and Nix files
• Updated README.md with instructions for enabling the git hook and reorganized development section

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.

File	Description
README.md	Added "Development" section with git hook setup instructions and reorganized existing installation content
AGENTS.md	New file providing comprehensive agent instructions including architecture, terminology, async patterns, and development workflow
.githooks/pre-commit	New pre-commit hook script that runs cargo fmt, clippy, and test before allowing commits
.editorconfig	New editorconfig file defining formatting standards for Rust (4 spaces), YAML (2 spaces), TOML (4 spaces), and Nix (2 spaces) files

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[feschber]

Maybe we should move the development instruction from the README to a CONTRIBUTING.md