Fix Fiori Elements Controller Extensions

Handle Fiori Elements V2 controller extensions during UI5 modernization. Use this skill when: - Extension controllers use `sap.ui.controller()` AND the manifest has a matching `controllerName` entry (Case B → report only, do not modernize) - Extension controllers use `Controller.extend()` with manifest `controllerName` registration (Case B → report only, do not modernize) - Code contains `registerControllerExtensions` calls (Case A → ControllerExtension.extend + override) - Manifest.json has `sap.ui5/extends/extensions/sap.ui.controllerExtensions` with `controllerName` entries Case B (plain object) is by far the most common. For Case B, do NOT modify controller files — re…