chore: enforce pre-PR validation (aggregate scripts, git hooks, PR checklist)

[brunoborges]

Description

Contributors occasionally open PRs that fail CI for avoidable reasons — most often Prettier format-check violations or a stale dist/ bundle — because the local format/lint/build/test steps weren't run before pushing. This PR adds lightweight tooling to make those checks easy to run and hard to forget.

This implements the agreed-upon enforcement measures (the maintainer enabled required status checks separately):

Aggregate npm scripts

• npm run check → format-check + lint + build + test (mirrors what CI runs).
• npm run fix → format + lint:fix + build.

Git hooks (husky + lint-staged)

Installed automatically on npm install via the prepare script:

• pre-commit runs lint-staged (Prettier + ESLint --fix on staged *.ts, Prettier on staged *.{yml,yaml}).
• pre-push runs npm run build && npm test.

PR template & docs

• Added a checklist item prompting contributors to run npm run check locally.
• Documented the aggregate scripts and hooks in docs/contributors.md.

Why dist/ is not auto-committed by CI

Auto-committing the rebuilt dist/ bundle from CI was deliberately excluded: writing to the repo from workflows that run untrusted PR code is a pwn-request security risk. The existing Check dist/ workflow continues to verify the committed bundle matches source.

Related issue

Follow-up to the maintenance discussion about contributors not running pre-PR checks (PRs #672 and #1017 failed solely on Prettier formatting).

Check list

• Ran npm run check locally (format, lint, build pass; the only failing test is a network-dependent JetBrains test that cannot reach CloudFront in the sandbox).
• Documentation updated.
• Tests added — N/A (tooling/CI change only).

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

[Copilot]

Pull request overview

This PR adds local, contributor-facing tooling to reduce avoidable CI failures by making the repo’s standard format/lint/build/test validations easier to run (via aggregate scripts) and harder to forget (via git hooks + checklist/docs).

Changes:

• Added aggregate npm scripts (check, fix) and configured lint-staged.
• Introduced Husky-managed pre-commit and pre-push hooks to run staged formatting/linting and build/tests.
• Updated contributor documentation and PR template to prompt running npm run check.

Show a summary per file

File	Description
package.json	Adds aggregate scripts, prepare hook install, lint-staged config, and new dev deps (husky/lint-staged).
package-lock.json	Locks new dev dependencies and their transitive dependencies.
docs/contributors.md	Documents the new check/fix scripts and the automated hooks.
.husky/pre-commit	Adds a pre-commit hook invoking lint-staged.
.husky/pre-push	Adds a pre-push hook running build + tests.
.github/pull_request_template.md	Adds a checklist item to run npm run check locally.

Copilot's findings

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• Files reviewed: 5/6 changed files
• Comments generated: 4