Add coding standards and other dev tools

[troychaplin]

What?

Adds the coding-standards toolchain for the plugin: Composer + PHPCS + PHPStan baseline, EditorConfig/.nvmrc, ESLint + Stylelint + lint-staged, a Husky pre-commit hook, a CI GitHub Actions workflow, GitHub issue templates (bug report / feature request), a PR template, and a base CONTRIBUTING.md.

Why?

Establishes consistent PHP/JS/CSS style and static analysis across the codebase, and gives contributors structured templates and documentation for filing issues and PRs, ahead of more people working on the plugin.

How?

• PHP: composer.json, phpcs.xml.dist, phpstan.neon.dist
• JS/CSS: package.json, eslint.config.js, .stylelintrc.json, .editorconfig, .nvmrc
• Pre-commit: .husky/pre-commit (lint-staged + project-wide PHPStan)
• CI: .github/workflows/ci.yml
• Templates/docs: .github/ISSUE_TEMPLATE/bug_report.yml, .github/ISSUE_TEMPLATE/feature_request.yml, .github/PULL_REQUEST_TEMPLATE.md, CONTRIBUTING.md

Testing Instructions

1. nvm use && composer install && npm i
2. Run npm run lint (JS, CSS, PHPCS, PHPStan) and composer phpstan to confirm the toolchain executes correctly.
   • Note: this currently surfaces pre-existing lint/PHPStan violations in the codebase — see Notes for Reviewers below.
3. Confirm the CI workflow runs via the Actions tab → CI → Run workflow (workflow_dispatch).

Changelog Entry

Developer - Add PHPCS/PHPStan/ESLint/Stylelint tooling, a pre-commit hook, a CI workflow, and GitHub issue/PR templates.

Checklist

• I have read the Contributing Guidelines
• npm run lint passes locally (JS, CSS, PHPCS, PHPStan) — not yet green repo-wide, see notes below
• I have manually verified this change using the steps in Testing Instructions
• I have updated relevant documentation (added CONTRIBUTING.md)

Notes for Reviewers

• CI is intentionally disabled (workflow_dispatch only) pending team review of the trigger conditions. See the commented-out on: block in ci.yml for the intended final config (push to main + pull requests). Will flip this once approved.
• The Husky pre-commit hook is present but fully commented out for the same reason — enabling it now would block every commit against the current lint/PHPStan state.
• After this PR merges, I'll take a pass at fixing the existing lint/PHPStan violations, likely split across smaller follow-up PRs rather than one large cleanup.

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[troychaplin]

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[troychaplin]

@aduth I reviewed the feedback you had on #2 and made these changes in this PR:

• Removed stylelint rule. I agree with you and updating the existing code will be worth the extra time.
• Node 24: I had updated that in this PR so we'll be well positioned once Gutenberg updates.
• Enforced linting on config files.
• Refactored styles while replacing Validation settings page with latest DataViews pacakage.

Other Notes:

• I usually use Breaking Changes at the top of my changelogs then follow the rest of the standard rules. I'm also ok with using conventional commits. I used what I know and mirrored the AI Labs plugin. Original comment

[joedolson]

In my opinion, we should merge this as it is and iterate. At these very early stages, I think it's better that we get some rules and standards in place early, and if we encounter a need to change things later, we can make those changes in smaller, more discrete changes where the reasoning can be more easily followed.