conformance: add an independent Python protocol runner

Implements the independent-runner requirement in stacksjs/stacks#2054 and exercises RFCs 0002–0004 without importing Stacks.js internals.

Deliverables

• Consume the checked-in language-neutral fixture JSON
• Exercise resolver, lifecycle, validation, errors, configuration, and persistence
• Emit a schema- and semantic-valid unverified conformance report
• Publish porting notes and ambiguity log
• Convert ambiguities into RFC issues or corrections
• Run the independent adapter in repository CI

Implemented in 7dc6f8d: independent standard-library Python runner with resolver, lifecycle, validation/error, configuration, and in-memory persistence adapters. It emits a structurally and semantically valid report with 15 passes, 0 failures, and no profile claim. Porting notes and ambiguity dispositions are public; CI publishes JSON and Markdown artifacts.