Dashboard widget:
- new 'Unified Risk Score (URS)' card above the existing compliance
widget. Hidden when no asset has a URS yet so empty installs stay
clean. Three columns:
* Avg URS (big colour-coded number per band)
* Severity spread badges (CRITICAL/HIGH/MEDIUM/LOW/NONE counts)
* Top-5 highest-risk assets with URS + severity pill
- 'Open >' link jumps to /compliance page
Asset edit modal:
- new 'Asset Criticality' dropdown (Low/Normal/High/Critical, with
the multiplier ×0.7..×1.5 shown next to each option for transparency)
- value preloaded from asset.criticality on edit, persisted via the
PUT /api/v1/assets/{id} endpoint extended in the previous commit