Backend returns metrics as an array, not an object.
- Update MetricsResponse type to use MetricDefinition[] instead of Record
- Remove Object.values() conversion in compare and rankings pages
- Fix useMetrics hook to handle array instead of object
- Fix getMetric to use array.find() instead of object indexing
Fixes empty metric dropdown on compare page.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>