Feat/issue 974 client response cache

[starsaintf]

Motivation and Context

How Has This Been Tested?

Breaking Changes

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[starsaintf]

Implemented the client-side TTL-honoring response cache requested in #974 for tools/list, prompts/list, resources/list, resources/templates/list, and resources/read.

The implementation includes TTL freshness, public/private cache scopes, authorization-context partitioning, pagination-aware cache keys, notification-driven invalidation, stale in-flight response protection, MRTR retry exclusion, configurable cache settings, tests, changelog updates, and client caching documentation.

The final branch passed the full repository-aligned verification matrix in GitHub Actions, including formatting, Clippy, all-feature and non-local tests, focused cache tests, conformance, SemVer, public API, coverage, audit, documentation, spelling, and example builds.

[alexhancock]

I assume #976 was a dupe?