chore(config): exclude pdfjs-dist from bundle and update asset tracing for standard fonts

Add 'pdfjs-dist' to serverExternalPackages in Next.js config to prevent bundling,
ensuring runtime resolution of on-disk assets like standard_fonts. Update
tracing includes for API preview route to explicitly cover worker and font
resources loaded dynamically.

next.config.ts

@@ -20,6 +20,10 @@ const serverExternalPackages = [
   '@napi-rs/canvas',
   'better-sqlite3',
   'ffmpeg-static',
+  // Keep pdfjs-dist out of the bundle: it resolves its own on-disk assets
+  // (standard_fonts) at runtime via require.resolve, which only works if it
+  // stays a real package in node_modules rather than being inlined.
+  'pdfjs-dist',
   ...(!bundleWorkerCompute ? ['onnxruntime-node', '@huggingface/tokenizers'] : []),
 ];
 
@@ -52,6 +56,9 @@ const nextConfig: NextConfig = {
       './node_modules/ffmpeg-static/ffmpeg',
     ],
     '/api/documents/blob/preview/ensure': [
+      // standard_fonts + the worker are loaded by path/specifier, not a static
+      // import, so trace them explicitly. The rest of pdfjs-dist is pulled in
+      // automatically now that it is a server-external package.
       './node_modules/pdfjs-dist/legacy/build/pdf.worker.mjs',
       './node_modules/pdfjs-dist/standard_fonts/**/*',
     ],