Refresh develop promotion with current main

[Serph91P]

Summary

• Merges the current main history into the verified develop promotion candidate.
• Preserves the exact develop tree while making both current branch tips ancestors of the refresh commit.
• Keeps stable promotion PR Promote verified develop release to main #757 unchanged and Draft pending exact-head review.

Verification

• Python 3.14: 165 backend tests passed with migrations verified.
• Ruff check and format verification passed.
• Node 24: ESLint, design-token lint, type-check, production build, and npm audit passed.
• pip-audit reported no known vulnerabilities.
• Docker image built successfully and passed container health plus frontend HTTP smoke checks.
• Gitleaks scanned the exported tree with no leaks found.
• The refresh commit tree matches the original develop tree exactly.

Notes

This PR intentionally contains only the merge commit required to refresh ancestry before the stable promotion review.

[Serph91P]

Reviewed exact head f81981ba2f908886cbb07fa13ed6046a82e734a6 against develop e1ca0a8fa0aa89c79583b317b12556fcec56f00c. The commit has the exact required parents, its tree 11ae1e6d8377ee8ac2a22f02a371001cb6b4094e matches the original develop tree, and an independent git merge-tree reproduces that tree with no content delta. Both required histories are ancestors, the stable promotion candidate is preserved, typography checks are clean for the refresh, and all 14 exact-head checks succeeded. No blocking findings.