Fix tournament roster and serve-order corruption guards

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Bug and impact

• Post-start group rebalancing and guest roster mutations could alter team/group assignments after matches already existed, leaving fixtures and standings inconsistent with persisted tournament state.
• setServeOrder accepted arbitrary player IDs/slots and scoring assumed Team A always occupied even serve slots, which could corrupt serving state or rotate the server incorrectly when Team B starts.

Root cause

• Some roster/group mutation paths missed the same started-tournament lock used elsewhere.
• Serve-order writes only checked array length, and point scoring derived serving side from index parity instead of the validated serve order.

Fix

• Block group rebalance and guest create/update/delete after a tournament has started.
• Add shared serve-order validation/default helpers, validate setServeOrder against the two match rosters, and use the configured order to determine serving side during point updates.
• Avoid rendering/tapping incomplete serve-order rows in the match UI.

Validation

• Added focused Vitest coverage for serve-order validation and serving-side derivation.
• Could not execute tests in this container because Node/npm are not available on PATH.

  

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Project	Deployment	Actions	Updated (UTC)
matchpoint	Ready	Preview, Comment	May 4, 2026 10:42am