Mover encuentros restantes de Umbral a las 14:00 Argentina

[SairaAsua]

Cambio

• mueve únicamente los encuentros públicos del 5 y 12 de septiembre a las 17:00 UTC / 14:00 Argentina
• conserva intactos los encuentros históricos, accesos y facilitadores
• agrega una regresión del contrato horario

Verificación

• vitest de public-cycle: 4/4
• git diff check: limpio

Pedido explícito de Sai el 1 de septiembre de 2026.

[compaii]

Superseded by the rollout-safe two-phase implementation:

• fix(landing): make 14:00 schedule rollout-safe #508 deployed the value-aware compatibility shim first.
• fix(live): move remaining Umbral sessions to 14:00 ART #509 then migrated only the September 5 and September 12 sessions to 17:00 UTC / 14:00 Argentina and removed the shim.

Production now serves 72e22ddf0cab3ce05d807215f20f0feef9f81110; both target rows were read back as SCHEDULED at 17:00 UTC, while the historical August rows retained their stored times. Closing this older combined PR without merging.