Release v1.9.2: Full-width background for code blocks

Fixed code block and ASCII art background to extend full paragraph width:
🔧 Background Fix:
- Moved shading (w:shd) from run level (<w:rPr>) to paragraph level (<w:pPr>)
- Background now extends full width like in the preview
- Applied to both createCodeBlockXml() and createAsciiArtXml() functions
📝 Technical Changes:
- src/wordTemplateExporter.js: Paragraph-level shading for full-width backgrounds
- Added w:ind with left="284" right="284" for consistent margins
- Removed redundant w:shd from run properties
🤖 Generated with [Claude Code](https://claude.com/claude-code)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "pan-converter",
-  "version": "1.9.1",
+  "version": "1.9.2",
   "description": "Cross-platform Markdown editor and converter using Pandoc",
   "main": "src/main.js",
   "scripts": {