Regenerate guide PDFs (#338)

## Summary
- Regenerated all 20 guide PDFs (EN and IT) with updated LaTeX engine
(xelatex)
- All PDFs have reduced file sizes

## Test plan
- [ ] Verify PDFs render correctly
- [ ] Spot-check content in EN and IT versions

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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Author: rjocham

scripts/Create-GuidePDFs.ps1

@@ -200,6 +200,7 @@ foreach ($guide in $guidesToProcess) {
             "--pdf-engine=$pdfEngine"
             "--lua-filter=$luaFilterPath"
             "--include-in-header=$latexHeaderPath"
+            "--resource-path=$contentDir"
             "-o", $outputPath
         )
 

scripts/callouts-latex.lua

@@ -4,6 +4,14 @@
 --
 -- Output: LaTeX environment with tcolorbox
 
+-- Strip leading "/" from image paths so --resource-path can resolve them
+function Image(el)
+  if el.src:sub(1, 1) == "/" then
+    el.src = el.src:sub(2)
+  end
+  return el
+end
+
 local function starts_with_callout_marker(inlines)
   if not inlines or #inlines == 0 then return nil end
   if inlines[1].t ~= "Str" then return nil end