Add Version field to extra for versioned entries

For versioned entries (e.g., dandi.000027/0.210831.2033), add
"Version: {version}" to the extra field. This ensures the version
appears in BibTeX exports, since BibTeX doesn't have a standard
version field.

Logic:
- Versioned entries (has / or @ in ID): "Version: 0.210831.2033"
- Latest entries (no / or @): "Current version: 0.210831.2033"

This distinguishes between:
- Specific version citation: dandi.000027@0.210831.2033
  Extra: Version: 0.210831.2033
- Latest version citation: dandi.000027
  Extra: Current version: 0.210831.2033

Both have versionNumber field set in Zotero, but the extra field
text clarifies the intent for BibTeX users.

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: yarikoptic

sandbox/update-zotero-collection

@@ -165,15 +165,20 @@ def bibtex_to_zotero_item(entry: Dict) -> Dict:
         citation_key = bibtex_id.replace("/", "@")
         item["extra"] += f"Citation Key: {citation_key}\n"
 
-        # For "latest" entries (no version in ID), extract version from DOI
-        # e.g., ID=dandi.000027, DOI=10.48324/DANDI.000027/0.210831.2033
-        if "/" not in bibtex_id and "@" not in bibtex_id and doi:
-            # Extract version from DOI (last part after /)
+        # Add version info to extra field for BibTeX export compatibility
+        # (since BibTeX doesn't have a standard version field)
+        if doi:
             doi_parts = doi.split("/")
             if len(doi_parts) >= 2:
                 version = doi_parts[-1]
-                # Add current version info to extra field
-                item["extra"] += f"Current version: {version}\n"
+                # Check if it looks like a version (not just a dandiset ID)
+                if "." in version and len(version) > 6:
+                    # For "latest" entries (no version in ID), use "Current version:"
+                    if "/" not in bibtex_id and "@" not in bibtex_id:
+                        item["extra"] += f"Current version: {version}\n"
+                    else:
+                        # For versioned entries, use "Version:"
+                        item["extra"] += f"Version: {version}\n"
 
     return item