Changes

• Flatten internal packages — move all classes fromcom.auth0.validators and com.auth0.cache into the root com.auth0 package
• Tighten access modifiers — make internal classes (JWTValidator, DPoPProofValidator, ClaimValidator, AuthConstants) package-private to define a clear public API surface
• Remove Spring Boot bridge layer — delete Auth0DomainResolver and Auth0RequestContext in favor of using the core DomainResolver and RequestContext types directly. This is enabled by changing auth0-api-java from implementation to api dependency so core types are transitively visible to consumers
• Auto-wire custom AuthCache bean — Auth0AutoConfiguration now accepts an optional AuthCache<Object> bean.
• Add MCD and caching documentation — comprehensive README sections covering static domain lists, dynamic resolvers, custom cache implementations, and default cache settings