html2pptx Unicode Path Fix

Problem

When the html2pptx pipeline processes HTML files located in directories with non-ASCII characters (e.g., 纯日语PPT/, 日本語資料/), PptxGenJS fails with ENOENT errors because the browser URL-encodes the file:// paths and PptxGenJS tries to open the encoded path literally on disk.

Context / Trigger Conditions

• Error message: ENOENT: no such file or directory with URL-encoded path like %E7%BA%AF%E6%97%A5%E8%AF%ADPPT
• Using html2pptx.js with background-image URLs or <img> tags
• HTML files or assets are in directories with CJK, accented, or other non-ASCII characters
• The build succeeds for all text/shape extraction but fails at pptx.writeFile() when PptxGenJS tries to read referenced image files

Solution