fix: use dynamic import instead of require for browser compatibility

- Replace require() with await import() for ES module compatibility
- Add async to setTimeout callback for dynamic import support

web/src/reader/reader-shell.ts

@@ -146,8 +146,9 @@ async function initializeReader(): Promise<void> {
     // Render the initial chapter content
     await renderSpineItem();
     // Initialize page calculation for dynamic page numbers
-    setTimeout(() => {
-      const { initializePageCalculation } = require("./core/reader-navigation");
+    setTimeout(async () => {
+      const { initializePageCalculation } =
+        await import("./core/reader-navigation");
       initializePageCalculation();
     }, 100);
   } catch (error) {