feat: add WP-7.6 release engineering

[fazpu]

Summary

• enforce one semantic version across PyPI, the shared GHCR image, and pinned Compose
• publish tagged releases through PyPI Trusted Publishing, GHCR, and GitHub Releases
• measure cold start through the first API query and drill migrations-before-process-restart
• document the final RememberStack / remember-stack identifiers and owner release setup

Verification

• 508 passed, 302 skipped locally
• lint-imports, Ruff, formatting, and Pyright pass
• release contract and client-wheel tests pass
• both Compose models resolve, including the one-argument upgrade gate
• website typecheck and production build pass
• all 100 eval-banana definitions validate
• corrected CI and coverage badge endpoints return HTTP 200
• Grok blocker review: no blockers after two upgrade-gate corrections

The local Docker daemon is unavailable. GitHub CI is the authoritative execution of the real PostgreSQL/Compose cold-start and upgrade drill.

[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.