KnownFix 0.3.8: complete MCP workflows

KnownFix 0.3.8 closes the remaining MCP workflow gaps identified by directory analysis. The remote server now publishes 12 tools, including a privacy-safe check_submission status lookup. audit_endpoint explicitly previews and redeems paid reports through the same tool, and get_skill clearly delivers assembled multi-fix bundles. All tools publish output schemas and all four MCP behavior annotations. Backend verification: 94 unit/security tests plus a live 12-tool contract readback. npm package and Registry manifest both point to the 0.3.8 backend and public storefront.