New cXML stream guide

.cursor/rules/docs.mdc

@@ -61,7 +61,7 @@ description: "Brief page description" # for SEO
 - **Titles**: Avoid gerunds in titles when practical ('Install package' rather than 'Installing the package')
 - **Sentence case**: Apply sentence case to card titles, tab titles, and pseudo-headers
 - **Pseudo-headers**: Titles made with simple bolded text (either on their own line or in lists with colons) should use sentence case
-- **Semantic line breaks**: Follow the SemBr specification by putting line breaks 
+- **Semantic line breaks**: Follow the SemBr specification by putting line breaks before and after major clauses. Links should occupy their own complete line. 
 
 ### Header formatting
 - Use sentence case for all headers (capitalize only the first word and proper nouns)
@@ -159,6 +159,15 @@ export const products = [
 - Provide alt text for custom images
 - Ensure proper focus management for interactive elements
 
+## Development and build commands
+
+### Package manager
+**This project uses Yarn, not npm.** Always use `yarn` for all package management commands.
+- Build: `yarn --cwd website build`
+- Develop: `yarn --cwd website start` (for local preview)
+- Install: `yarn install`
+- Do NOT use: `npm install`, `npm run`, `npx` - use `yarn` equivalents instead
+
 ## Quality assurance
 
 ### Content review checklist