macOS: declare PDF by UTI so Open With recommends PrintCraft (#176)

CFBundleDocumentTypes listed PDF by extension and MIME type only.
LaunchServices keeps those as plain tags (.pdf, application/pdf)
instead of resolving them to com.adobe.pdf, so Finder greys the app
out under Open With > Recommended Applications and a forced open
fails with 'cannot open files in the PDF document format'.

Add LSItemContentTypes com.adobe.pdf (keeping extension and MIME for
backward compatibility). Role stays Editor, rank stays Alternate, so
the app is offered without hijacking the default. Verified with
lsregister -dump: bindings change from '.pdf, application/pdf' to
'com.adobe.pdf' with claimed UTIs com.adobe.pdf; plutil -lint and
xmllint --noout pass.

Follow-up to #73.

Co-authored-by: Brandon Thomas <echelon@gmail.com>

packaging/macos/Info.plist.in

@@ -47,7 +47,8 @@
 
   <!-- Documents PdfCraft opens (#73): it is offered under Open With and can be made the default
        for PDFs, without taking over from the system's viewer on install ("Alternate"). Declared by
-       extension and MIME type; LaunchServices maps them to the system's PDF type. Finder hands the
+       UTI (LSItemContentTypes, what modern macOS filters Open With > Recommended Applications on),
+       plus extension and MIME type for backward compatibility. Finder hands the
        file over as an Apple event, which apps/pdfcraft/src/apple_events.rs receives. -->
   <key>CFBundleDocumentTypes</key>
   <array>
@@ -58,6 +59,8 @@
       <string>Editor</string>
       <key>LSHandlerRank</key>
       <string>Alternate</string>
+      <key>LSItemContentTypes</key>
+      <array><string>com.adobe.pdf</string></array>
       <key>CFBundleTypeExtensions</key>
       <array><string>pdf</string></array>
       <key>CFBundleTypeMIMETypes</key>