Add ESLint and Prettier with consistent formatting standards

- Add ESLint 9 and Prettier for consistent code formatting across docs repos
- Configure ESLint with TypeScript and Astro support
- Standardize lint and format commands across all repositories
- Upgrade to ESLint 9 flat config format (eslint.config.js)
- Update all ESLint and Prettier packages to latest versions
- Add CI checks to enforce formatting standards

Author: JonathanMatthey

.github/pull_request_template.md

@@ -0,0 +1,19 @@
+## Changes proposed in this pull request
+
+<!--
+Provide a succinct description of what this pull request entails.
+-->
+
+## Context
+
+<!--
+What were you trying to do?
+Link issues here -  using `fixes #number`
+-->
+
+## Checklist
+
+- [ ] I have run `bun run format` to ensure code is properly formatted
+- [ ] I have verified that `bun run lint` passes without errors
+
+

.github/workflows/test-build.yml

@@ -17,5 +17,7 @@ jobs:
 
       - name: Install dependencies
         run: bun install
+      - name: Run ESLint
+        run: bun run lint
       - name: Test build website
         run: bun run build

README.md

@@ -52,9 +52,20 @@ All commands are run from the root of the project, from a terminal:
 | `bun run preview`         | Preview your build locally, before deploying     |
 | `bun run astro ...`       | Run CLI commands like `astro add`, `astro check` |
 | `bun run astro -- --help` | Get help using the Astro CLI                     |
+| `bun run format`          | Fix linting issues                            |
+| `bun run lint`            | Check linting                                  |
 
 You can substitute the `bun` commands with whatever package manager of your choice uses.
 
+### 🔍 Code Linting
+
+This project uses [ESLint](https://eslint.org/) for code linting. Before submitting a pull request, please ensure your code passes linting:
+
+1. **Fix issues**: Run `bun run format` to automatically fix linting issues
+2. **Check before pushing**: Run `bun run lint` to verify everything passes (CI will also run this)
+
+ESLint is configured to work with TypeScript and Astro files. The configuration extends recommended rules from ESLint, TypeScript ESLint, and Astro ESLint plugins.
+
 ### 👀 Want to learn more?
 
 Check out [Starlight’s docs](https://starlight.astro.build/), read [the Astro documentation](https://docs.astro.build), or jump into the [Astro Discord server](https://astro.build/chat).