WCIF/Reg 2026: Support Dual Rounds (linked rounds)

[coder13]

WCA 2026 regs introduce Dual Rounds (two consecutive rounds linked together for progression/ranking rules). DelegateDashboard needs to handle competitions using this feature.

Reference:

• WCA announcement: https://www.worldcubeassociation.org/posts/wca-regulations-january-2026 (Major change: Dual Rounds)
• Regulations PR: Introduce Dual Rounds thewca/wca-regulations-january-2026#50
• WCA site implementation uses a linked rounds model. In the WCA website repo, schedule UI receives a linkedRounds map keyed by WCIF round id, and the live results API includes linked_round_ids on rounds.
  • Example schema: https://github.com/thewca/worldcubeassociation.org/blob/master/next-frontend/openapi/schemas/live/LiveRound.yaml

Likely impacts in DelegateDashboard

1. Round validation

• src/lib/wcif/validation/eventRoundValidation.ts currently requires advancementCondition on every non-final round.
• Dual rounds may need an exception (e.g., round1 of a linked pair may be allowed to omit/alter advancementCondition), depending on how WCIF encodes the link.

2. UI / exports / imports

• Anywhere we render a round name/format/proceed text should be able to indicate dual rounds and/or treat linked rounds as a combined unit.
• CSV export fields advancement_condition and round listings may need to incorporate the dual-round semantics.

3. Data model/types

• Confirm how the WCIF (or WCA API WCIF wrapper) represents linked/dual rounds. If the WCIF schema adds fields, update @wca/helpers types usage and our internal mocks/builders.

Acceptance criteria

• Identify the exact WCIF/API shape for dual rounds (field names + where they live).
• Update validation so dual rounds do not trigger false-positive errors.
• Ensure any round lists/exports/imports handle the linked rounds without crashes.
• Add tests covering a dual-round example WCIF.