Add class override system for framework customization

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docs/CLAUDE.dist.md

@@ -102,6 +102,22 @@ Classes are namespacing tools. Use static unless instances needed (models, resou
 
 **Commit discipline**: ONLY commit when explicitly asked. Commits are milestones, not individual changes.
 
+### Class Overrides
+
+To customize framework classes without modifying `/system/`, copy them to `rsx/` with the same class name. The manifest automatically uses your version and renames the framework file to `.upstream`.
+
+**Common override targets** (copy from `system/app/RSpade/Core/Models/`):
+- `User_Model` - Add custom fields, relationships, methods
+- `User_Profile_Model` - Extend profile data
+- `Site_Model` - Add site-specific settings
+
+```bash
+cp system/app/RSpade/Core/Models/User_Model.php rsx/models/user_model.php
+# Edit namespace to Rsx\Models, customize as needed
+```
+
+Details: `php artisan rsx:man class_override`
+
 ### DO NOT RUN `rsx:clean`
 
 **RSpade's cache auto-invalidates on file changes.** Running `rsx:clean` causes 30-60 second rebuilds with zero benefit.