Fix Fiori Elements Controller Extensions

This skill handles Fiori Elements V2 controller extensions during UI5 modernization. There are two cases with different actions:

Case B (most common): Extensions registered via controllerName in manifest → Report only. Do NOT modify the controller files. Leave them as-is and inform the user which files need manual attention.
Case A (rare): Extensions using registerControllerExtensions → Perform the full modernization to ControllerExtension.extend() + manifest registration.

Linter Rules Handled

Rule ID	Message Pattern	This Skill's Action
`no-deprecated-api`	Use of deprecated `registerControllerExtensions`	Case A: Modernize to manifest + ControllerExtension
`no-deprecated-api`	Use of deprecated `sap.ui.controller`	Case B (if manifest has `controllerName`): report only, do not fix; Case A (if `registerControllerExtensions`): ControllerExtension class
`no-deprecated-api`	Use of deprecated `Controller` (from `sap/ui/core/mvc/Controller`)	Case B: report only, do not fix