Restore source media precedence and roulade diagnostic horizon

[ob1-s]

Follow-up to #21.

• keep publisher/source media primary for listing cards; use registry renders only as fallback
• show registry simulation media separately from publisher media on detail pages
• separate the official roulade command window from the registry recovery/settle capture horizon
• add regressions for source/registry/duckmark media selection and full-horizon evaluation
• Verification: root Python 23 passed; simulation Python 41 passed; Vitest 20 passed; typecheck, registry validation, production build, and git diff --check passed. The real roulade render covers 4.0s/200 steps and passes recover_upright after the 3.0s tail.