fix: 🐛 support path attribute in @FeignClient and refactor annotation constants

[linwumingshi]

• Support the path attribute of @FeignClient for base URL configuration in API documentation.
• Refactor SpringBootDocBuildTemplate to extract mapping annotations into buildSpringMappingAnnotations() method for better maintainability.
• Add new constants in DocAnnotationConstants: CONSUMES, PRODUCES, METHOD, PARAMS, and PATH_MAPPING_PROPS.
• Deprecate misnamed REQUEST_HERDER and introduce correct REQUEST_HEADER in SpringMvcAnnotations.
• Update SpringMVCRequestHeaderHandler and JavaClassValidateUtil to use the new REQUEST_HEADER constant.
• Improve code consistency by using constants instead of string literals across annotation processing.
• Update copyright year to 2025 across relevant files.

Fixes #1114

[github-actions]

@linwumingshi

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