Add public repository reanalysis workflow to main

[htsugawa]

Summary

• add metadata-driven public repository reanalysis for Metabolomics Workbench, MetaboLights, MB-POST, and MetaboBank
• add raw-data download, recognition, metadata projection, retention policy, QA evidence, and agent/MCP workflows
• improve publication reporting, LLM settings, job provenance, and download progress UX

Note

PR #7 was merged into a branch that had already been merged to main. This PR delivers that completed stacked work to main.

Validation

• python -m unittest discover -s tests -v (105 passed on the follow-up branch)