chore: add OSS related docs

Author: grega

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @grega

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,27 @@
+## Summary
+
+Describe the issue.
+
+## Steps to reproduce
+
+1. 
+2. 
+3. 
+
+## Expected behaviour
+
+Describe what you expected to happen.
+
+## Actual behaviour
+
+Describe what happened instead.
+
+## Environment
+
+- Runtime: 
+- Browser or platform: 
+- Package version: 
+
+## Additional context
+
+Add any other useful details, screenshots, or example code.

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,14 @@
+## Summary
+
+Describe the change.
+
+## Testing
+
+- [ ] `npm test`
+- [ ] Additional manual testing completed
+
+## Checklist
+
+- [ ] Linked relevant issue, if applicable
+- [ ] Updated tests, if needed
+- [ ] Updated docs, if needed

CONTRIBUTING.md

@@ -0,0 +1,48 @@
+# Contributing
+
+## Prerequisites
+
+- **asdf** for environment management  
+- **Node.js** (installed via asdf)  
+- **npm** (bundled with Node)
+
+## Development setup
+
+Follow the guide at [asdf-vm.com](https://asdf-vm.com/).
+
+Then install the Node.js plugin:
+
+```bash
+asdf plugin add nodejs
+asdf install
+```
+
+This will read `.tool-versions` and install the appropriate version of Node.js automatically.
+
+```bash
+npm install
+npm run build -- --watch
+```
+
+## Tests
+
+```bash
+npm test
+```
+
+To continuously watch for file changes:
+
+```bash
+npm run dev:test
+```
+
+## Pull requests
+
+- Keep changes focused and small where possible.
+- Add or update tests when behaviour changes.
+- Update documentation when public APIs or workflows change.
+- Make sure tests pass before opening a pull request.
+
+## Reporting issues
+
+When reporting a bug, include the Python code, the runtime you used, the error you received, and the behaviour you expected.

README.md

@@ -48,43 +48,17 @@ See the [demo](docs/README.md) for a full set of examples.
 
 ## Development
 
-### Prerequisites
+See [CONTRIBUTING.md](CONTRIBUTING.md) for detailed instructions.
 
-- **asdf** for environment management  
-- **Node.js** (installed via asdf)  
-- **npm** (bundled with Node)
-
-### Set up
-
-Follow the guide at [asdf-vm.com](https://asdf-vm.com/).
-
-Then install the Node.js plugin:
+In brief:
 
 ```bash
-asdf plugin add nodejs
-asdf install
-```
-
-This will read `.tool-versions` and install the appropriate version of Node.js automatically.
-
-```
 npm install
 npm run build -- --watch
-```
-
-### Tests
-
-```
 npm test
 ```
 
-To continuously watch for file changes:
-
-```
-npm run dev:test
-```
-
-### Building
+## Building
 
 Create a clean build for distribution:
 
@@ -98,7 +72,7 @@ You can now import, and use it, elsewhere (see Usage notes).
 
 The package is published to: https://github.com/RaspberryPiFoundation/python-friendly-error-messages/pkgs/npm/python-friendly-error-messages
 
-### Publishing
+## Publishing
 
 ```bash
 npm publish