[KomachiSion]

What is the purpose of the change

Resolve HEAD requests to their GET controller method in ControllerMethodsCache on v2.x. Previously, a HEAD request to a GET mapping returned no cached method even though Spring MVC accepts the request.

Brief changelog

• Normalize HEAD to GET when constructing the lookup key, preserving parameter matching and the original servlet request method.
• Add JUnit 5 regressions for HEAD and GET lookup, matching and mismatching parameters, POST behavior, and missing mappings.

Verifying this change

• The regression tests reproduced both HEAD lookup failures before the fix.
• Run with Java 8: mvn -B -pl core -am clean package apache-rat:check findbugs:findbugs -Dmaven.test.skip=false -DskipTests=false -Dtest='ControllerMethodsCacheTest,ParamRequestConditionTest,PathRequestConditionTest' -Dsurefire.failIfNoSpecifiedTests=false.
• All 10 selected tests passed; the complete core dependency reactor passed packaging, RAT, Checkstyle, and FindBugs execution.
• Spotless apply/check with a temporary unused-import configuration for the two changed Java files; this branch has no configured Spotless formatter. The branch's Checkstyle runs as part of Maven validation.

No endpoint or public SDK contract changes.

[github-actions]

Thanks for your this PR. 🙏
Please check again for your PR changes whether contains any usage/api/configuration change such as Add new API , Add new configuration, Change default value of configuration.
If so, please add or update documents(markdown type) in docs/next/ for repository nacos-group/nacos-group.github.io

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感谢您提交的PR。 🙏
请再次查看您的PR内容，确认是否包含任何使用方式/API/配置参数的变更，如：新增API、新增配置参数、修改默认配置等操作。
如果是，请确保在提交之前，在仓库nacos-group/nacos-group.github.io中的docs/next/目录下添加或更新文档（markdown格式）。