[NA] [FE] Fixed UI issues when optimizer baseline score was 0

[jverre]

Details

When the baseline score for an optimization run was 0, there were a number of issues:

1. No "Best prompt" tag in the chart
2. No scores in the table
3. No prompt diff

This PR addresses all of these:

Change checklist

• User facing
• Documentation update

Issues

• Resolves #
• OPIK-000

Testing

Tested locally

Documentation

N/A

[Copilot]

Pull Request Overview

This PR fixes display issues in the optimization comparison UI when the baseline score is zero. The fix ensures proper rendering of scores, trend indicators, and prompt diffs by replacing percentage-based comparisons with absolute difference calculations when percentage calculations are not possible.

Key changes:

• Modified trend calculation logic to use absolute differences instead of percentages when baseline is 0
• Added visual indicators (TrendingUp/TrendingDown/MoveRight icons with Tags) for absolute score changes
• Preserved percentage-based trend display when baseline is non-zero

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
ObjectiveScoreCell.tsx	Implements absolute difference display with trend icons when percentage calculation isn't possible
CompareOptimizationsPage.tsx	Removes early return that prevented score calculation when baseline is 0, adds baseScore to column metadata
BestPrompt.tsx	Adds absolute difference calculation and corresponding visual indicators for the best prompt card