chore: publish accumulated main changes

[Oneiros667]

Summary

• Publish the complete local main tree through the protected main branch workflow.
• Flatten the unpublished history into one linear commit so it complies with the no-merge-commits rule.
• Preserve the exact local main tree; local main remains unchanged.

Verification

• .NET restore, build, tests, and format check passed.
• Python: 257 tests passed; Ruff and deterministic MCP fixture evaluation passed.
• Markdown lint, publication safety, workflow, conventional-commit, and whitespace checks passed.
• Six .NET tests skipped because MongoDB, Neo4j, Qdrant, and the optional sample configuration were unavailable.
• Markdown-link check remains blocked by two pre-existing ignored CodeQL README links under .codemesh-evals.