Reset replacement selection when the performance scale modal closes

[coderabbitai]

Summary

ReplacementSelectionModal retains selectedReplacementId after the modal closes.

Required change

Reset the selected replacement when the modal closes and when the target performance scale changes. The delete action must require a replacement selected during the current modal session.

Rationale

The parent keeps the modal component mounted. Closing it sets scaleToDelete to null, but the component state persists. When an administrator opens the modal again, the next delete request can submit the prior replacement ID.

Affected area

• src/app/admin/performance/components/ReplacementSelectionModal.tsx
• src/app/admin/performance/page.tsx

Acceptance criteria

• Canceling the modal clears selectedReplacementId.
• A successful replacement clears selectedReplacementId.
• Opening the modal for a different performance scale starts with no replacement selected.
• The Delete and Replace button remains disabled until the administrator selects a replacement in the current session.

Backlinks

• Pull request: feat: v0.15.0 #469
• Review comment: feat: v0.15.0 #469 (comment)
• Requested by: @Producdevity