fix: handle FFmpeg dynamic import more gracefully

- lazy-load FFmpeg class to avoid static analysis issues
- add proper null checks for FFmpeg instance
- use initFFmpeg() helper to manage async initialization
- fixes bundler 'too dynamic' error with static-friendly approach

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

lib/media/wasm/wasmLoader.ts

@@ -1,7 +1,23 @@
-import { FFmpeg } from '@ffmpeg/ffmpeg';
+import type { FFmpeg as FFmpegType } from '@ffmpeg/ffmpeg';
 import { initializeImageMagick } from '@imagemagick/magick-wasm';
 import type { ConverterEngine, WASMModuleState } from '@/types/media';
 
+// Dynamically require FFmpeg to avoid bundler issues
+let FFmpeg: any = null;
+
+// Initialize FFmpeg at module load time
+async function initFFmpeg() {
+  if (!FFmpeg) {
+    try {
+      const module = await import('@ffmpeg/ffmpeg');
+      FFmpeg = module.FFmpeg;
+    } catch (error) {
+      console.error('[FFmpeg] Failed to import module:', error);
+    }
+  }
+  return FFmpeg;
+}
+
 /**
  * WASM module loading state
  */
@@ -13,21 +29,32 @@ const moduleState: WASMModuleState = {
 /**
  * Cached WASM instances
  */
-let ffmpegInstance: FFmpeg | null = null;
+let ffmpegInstance: FFmpegType | null = null;
 let imagemagickInstance: any = null;
 
 /**
  * Load FFmpeg WASM module
  */
-export async function loadFFmpeg(): Promise<FFmpeg> {
+export async function loadFFmpeg(): Promise<FFmpegType> {
   if (ffmpegInstance && moduleState.ffmpeg) {
     return ffmpegInstance;
   }
 
   try {
-    ffmpegInstance = new FFmpeg();
+    // Initialize FFmpeg class if not already done
+    const FFmpegClass = await initFFmpeg();
+    
+    if (!FFmpegClass) {
+      throw new Error('FFmpeg class not available');
+    }
 
-    ffmpegInstance.on('log', ({ message }) => {
+    ffmpegInstance = new FFmpegClass();
+
+    if (!ffmpegInstance) {
+      throw new Error('Failed to create FFmpeg instance');
+    }
+
+    ffmpegInstance.on('log', ({ message }: { message: string }) => {
       console.log('[FFmpeg]', message);
     });