Add auto-loading of module permissions in RolePermissionSeeder

RolePermissionSeeder now automatically scans app/Modules/*/Permissions.php
files and registers all permissions found. No manual registration required.

- Added loadModulePermissions() method to scan module directories
- Changed givePermissionTo() to syncPermissions() for idempotency
- Updated Modules README to document auto-loading
- Updated CLAUDE.md to reflect auto-loading behavior

src/app/Modules/README.md

@@ -94,6 +94,9 @@ ## Permissions
 ];
 ```
 
+**Permissions are auto-loaded!** When you run `php artisan db:seed --class=RolePermissionSeeder`, 
+it scans all `app/Modules/*/Permissions.php` files and registers them automatically.
+
 Use in Blade:
 ```blade
 @can('stock_management.view')