Remove executable Dolt validator package - #9

What changed

• removes the installable openstatspec-specification Python package
• removes the executable Dolt declaration validator, its tests, and its tool wrapper
• removes package installation and validator-test steps from specification CI
• removes the package-specific PyPI publishing workflow
• removes the unreleased 0.2.1 package path from the changelog and roadmap
• removes the validator-coupled Dolt declaration manifest and empty evidence-registry guidance
• records that Transformation Plan/frontend profile 0.2 is already merged

What remains

• the authoritative Dolt dialect profile in sql/dialect-profile-baseline.json
• existing cross-adapter capability declaration requirements in the normative SQL profile documents
• existing specification repository validation
• all pending adapter, service-matrix, exact-commit, and tag-protection gates for v0.3.0

Architecture boundary

The specification repository publishes normative documentation, schemas, and declarative fixtures. Executable adapter/declaration validation belongs in implementation or adapter repositories.

Validation

• python3 tools/validate_repository.py
• git diff --check
• exact-head CI: https://github.com/OpenStatSpec/specification/actions/runs/30906027254
• independent strong review: clean

Release impact

No corrective release is required. openstatspec-specification==0.2.1 was never published, and no v0.2.1 tag or GitHub Release exists. Keep this work under Unreleased; the next possible specification release remains v0.3.0 after the documented gates pass.