feat(initial): add comprehensive PDF to JPEG preview library with dual-environment support

- Add Node.js implementation using @push.rocks/smartpdf
- Add browser implementation with PDF.js and Web Workers
- Support configurable quality, dimensions, and page selection
- Include comprehensive TypeScript definitions and error handling
- Provide extensive test coverage for both environments
- Add download functionality and browser compatibility checking

ts_web/index.ts

@@ -0,0 +1,37 @@
+/**
+ * @push.rocks/smartpreview - Web implementation
+ * 
+ * A library for generating efficient JPEG previews from PDFs
+ * in browser environments using PDF.js and Web Workers.
+ */
+
+// Main classes
+export { SmartPreview } from './smartpreview.js';
+export { WebPdfProcessor } from './pdfprocessor.js';
+
+// Runtime exports (classes and functions)
+export {
+  PreviewError
+} from './interfaces.js';
+
+// Type-only exports (interfaces and types)
+export type {
+  IPreviewOptions,
+  IPreviewResult,
+  TWebInputType,
+  TSupportedInputFormat,
+  TSupportedOutputFormat,
+  IWebFormatProcessor,
+  IWebPdfProcessor,
+  TPreviewError,
+  IProgressCallback,
+  IWebPreviewOptions,
+  // Worker-related types
+  TWorkerMessageType,
+  IWorkerMessage,
+  IPdfProcessRequest,
+  IPdfProcessResponse
+} from './interfaces.js';
+
+// Default export for convenience
+export { SmartPreview as default } from './smartpreview.js';