sloproxy

feat(htmlsanitize): add HTML and JSON sanitization utilities with integration across plugins and APIs master

- Introduced `htmlsanitize` package for escaping HTML and handling JSON body sanitization to prevent XSS vulnerabilities. - Integrated sanitization functions into plugin store, plugin host, and API management handlers to ensure all user-facing content is escaped. - Added unit tests to verify proper escaping of HTML strings, JSON bodies, and nested data structures. - Updated existing management and plugin-related tests to validate sanitization implementations.