WW-5622 Optimize Hibernate proxy detection when Hibernate is absent

[lukaszlenart]

Summary

• Detect Hibernate availability once at class-load time via Class.forName() in ProxyUtil
• Short-circuit isHibernateProxy(), isHibernateProxyMember(), and getHibernateProxyTarget() immediately when Hibernate is absent
• Retain existing catch (NoClassDefFoundError) blocks as safety net (intentionally narrower than LinkageError — broken Hibernate installs should fail visibly)

Problem

When Hibernate is not on the application classpath, every call to Hibernate proxy detection methods throws and catches NoClassDefFoundError. Since isProxy() and isProxyMember() are invoked on every OGNL evaluation, this produces hundreds of thousands of caught exceptions, causing severe performance degradation.

Backport of #1649 (Struts 7) to release/struts-6-8-x.

Fixes WW-5622

Test plan

• SpringProxyUtilTest — 3 tests pass
• Core util.** tests — 89 pass (4 failures in unrelated DefaultFileManagerTest)
• Manual verification in app without Hibernate on classpath

🤖 Generated with Claude Code

[sonarqubecloud]

Quality Gate failed

Failed conditions
25 Security Hotspots
43.3% Coverage on New Code (required ≥ 80%)
3.3% Duplication on New Code (required ≤ 3%)
E Security Rating on New Code (required ≥ A)
E Reliability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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