Possible issue with Eclipse plugin

### Issue:
* Just bumped to `1.36.0`, I have a save action to format automatically, getting this error:
* A save participant caused problems. The save participant 'Code Clean Up' caused an exception: `java.lang.NoClassDefFoundError: Could not initialize class com.google.googlejavaformat.java.javadoc.MarkdownPositions`. See the error log for details.
* Explicit invocation of the formatter (Shift + Ctrl + F) does nothing.
* External runs via java -jar are fine.

### Environment:
* Eclipse IDE for Java Developers (includes Incubating components)
* Version: 2026-06 (4.40.0)
* Build id: 20260604-0653
* OS: Linux, v.7.1.5-arch1-2, x86_64 / gtk 3.24.52, WebKit 2.52.5
* Java vendor: Eclipse Adoptium
* Java runtime version: 21.0.11+10-LTS
* Java version: 21.0.11

Ask me anything, will try to help.

Start by reproducing the failure through the Eclipse save participant 'Code Clean Up' and the explicit formatter shortcut, using the reported Eclipse, Java 21, and Linux environment. Compare both behaviors with the working external java -jar invocation. Done means the Eclipse plugin formats successfully without the MarkdownPositions initialization error while standalone formatting remains working.

索引モデルが issue の本文から書いたものです。