Improve TypeScript types and error handling

- Created proper TypeScript types for Office API operations
- Replaced 'any' casts with appropriate types
- Added type-safe utility functions in office-types.ts
- Improved error handling with proper unknown type
- Added helper functions for PowerPoint shape operations
- Created proper TypeScript interface for webpack HMR

These changes improve code quality, maintainability, and help catch potential bugs at compile time rather than runtime.

🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>

src/taskpane/types/office-types.ts

@@ -0,0 +1,48 @@
+/**
+ * Type definitions for the Office JS API 
+ */
+
+/**
+ * Extended Error interface for Office/PowerPoint API errors
+ */
+export interface OfficeApiError extends Error {
+  code?: string;
+  debugInfo?: {
+    code?: string;
+    message?: string;
+    errorLocation?: string;
+    statement?: string;
+    innerError?: any;
+  };
+}
+
+/**
+ * Helper to safely extract error message from any error object
+ */
+export function getErrorMessage(error: unknown): string {
+  if (error instanceof Error) {
+    return error.message;
+  }
+  return String(error);
+}
+
+/**
+ * Type-safe wrapper for PowerPoint API operations on shapes
+ */
+export function isPictureShape(shape: PowerPoint.Shape): boolean {
+  return shape.type === PowerPoint.ShapeType.image;
+}
+
+/**
+ * Type-safe wrapper for working with PowerPoint slides
+ */
+export function getFirstSelectedSlide(context: PowerPoint.RequestContext): PowerPoint.Slide {
+  return context.presentation.getSelectedSlides().getItemAt(0);
+}
+
+/**
+ * Type-safe utility for selecting shapes
+ */
+export function selectShapesById(slide: PowerPoint.Slide, shapeIds: string[]): void {
+  slide.setSelectedShapes(shapeIds);
+}