[fix] Remove dynamic import race condition in file handling

Replace dynamic import with static import in handleFile method to eliminate race condition causing Playwright test flakiness.

The dynamic import introduced asynchronous behavior that created timing issues in tests expecting immediate file processing completion.

Fixes #3955 test flakiness

Author: christian-byrne

src/scripts/app.ts

@@ -52,6 +52,7 @@ import type { ComfyExtension, MissingNodeType } from '@/types/comfy'
 import { ExtensionManager } from '@/types/extensionTypes'
 import { ColorAdjustOptions, adjustColor } from '@/utils/colorUtil'
 import { graphToPrompt } from '@/utils/executionUtil'
+import { getFileHandler } from '@/utils/fileHandlers'
 import {
   executeWidgetsCallback,
   fixLinkInputSlots,
@@ -1262,7 +1263,6 @@ export class ComfyApp {
    * @param {File} file
    */
   async handleFile(file: File) {
-    const { getFileHandler } = await import('@/utils/fileHandlers')
     const removeExt = (f: string) => {
       if (!f) return f
       const p = f.lastIndexOf('.')