Pin the conformance CLI to the alpha dist-tag

[koic]

Motivation and Context

The npm latest dist-tag of @modelcontextprotocol/conformance points at 0.1.16, the old 0.1 line, while the 2026-07-28 requirement revisions and the frozen-requirements framework live in the 0.2.0 alpha line (alpha currently resolves 0.2.0-alpha.11). The runners invoked the bare package name, so rake conformance and the conformance CI job resolve whatever latest points at: a fresh machine silently downgrades to the old suite while a warm npx cache may keep serving a newer one, and the suite actually in use depends on the environment. Pinning the alpha dist-tag puts every run on the line the frozen conformance requirements are anchored to (0.2.0-alpha.10, published 2026-07-27).

Running the real alpha suite surfaced the actual client-leg state, so the expected-failures baseline is updated to match: initialize now passes (the harness accepts 2026-07-28, fulfilling the TODO on the old entry), and the scenarios pending client-side work are recorded with their reasons: the 2026-07-28 stateless lifecycle and the SEP-2322 MRTR driver, SEP-2243 custom-header mirroring, client-side JSON Schema preservation, the DPoP and WIF authorization extensions, and one auth/authorization-server-migration check added to the suite after the alpha.10 anchor.

The manual npx examples in conformance/README.md carry the same pin so local reproduction runs the same suite as the rake task.

How Has This Been Tested?

npx --yes @modelcontextprotocol/conformance@alpha --version resolves 0.2.0-alpha.11, and bundle exec rake conformance passes the baseline check on both legs: the server leg reports 73 passed with 0 failed and no expected failures, and the client leg fails exactly the scenarios the baseline records.

Breaking Changes

None. The change is confined to the conformance tooling; the shipped gem is untouched.

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

[koic]

Merging via bypass to use this as the baseline for verifying 2026-07-28 specification coverage.