Adds a CategoryFilterBar with pill-shaped FilterChip components below the
metric health cards. Non-metric categories (Missing_AppID, Aging Vulns,
Missing_DF, etc.) are derived dynamically from device data and displayed
as color-coded filterable chips with device counts.
Unified filter state replaces the old metricFilter array, ensuring mutual
exclusivity between metric card filters and non-metric chip filters.
Includes 4 property-based tests validating derivation, filter predicate,
mutual exclusivity, and color resolution correctness.
Closes#26
