Bump version to 4.0.0-SNAPSHOT for Spring Boot 4 compatibility

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: devondragon

gradle.properties

@@ -1,3 +1,3 @@
-version=3.5.2-SNAPSHOT
+version=4.0.0-SNAPSHOT
 mavenCentralPublishing=true
 mavenCentralAutomaticPublishing=true