feat!: upgrade to Spring Boot 4.0.0

BREAKING CHANGE: Requires Java 17+ (previously Java 8). Spring Boot upgraded from 2.7.12 to 4.0.0 with package restructuring and Jakarta EE migration.

Co-authored-by: nomeguy <85475922+nomeguy@users.noreply.github.com>

Author: Copilot

.semantic-release-trigger

@@ -0,0 +1,6 @@
+# Semantic Release Trigger
+
+This file triggers a major version release via semantic-release.
+
+Upgrade: Spring Boot 2.7.12 -> 4.0.0
+Breaking: Requires Java 17+ (was Java 8)