📝 docs: add Git branch naming convention to CLAUDE.md

Add standardized branch naming pattern for features and bugfixes:
- Format: feature/{task-id}-{short-description}
- Use English kebab-case
- Start with task/issue ID
- Include example for clarity

CLAUDE.md

@@ -230,6 +230,13 @@ isDesktop = breakpoint([Breakpoint.Desktop, Breakpoint.DekstopL, Breakpoint.Deks
 
 ### Project Conventions
 - **Default Branch**: `develop` (not main) - Always create PRs against develop
+- **Branch Naming**: When starting work on a new feature or bug, create a branch following this pattern:
+  - Format: `feature/{task-id}-{short-description}` or `bugfix/{task-id}-{short-description}`
+  - Use English kebab-case for the description
+  - Start with the task/issue ID (e.g., `5391`)
+  - Keep description concise - shorten if the full title is too long
+  - Example: For task "#5391 Prämie Checkout // Action Card - Versandbestellung"
+    - Branch: `feature/5391-praemie-checkout-action-card-delivery-order`
 - **Commit Style**: [Conventional commits](https://www.conventionalcommits.org/) without co-author tags
 - **Nx Cache**: Always use `--skip-nx-cache` for tests to ensure fresh results
 - **Testing**: New libraries use Vitest + Angular Testing Utilities; legacy use Jest + Spectator