feat(ui): scope, freshness and jurist-review badges + live empty-state

Adds three dark-first chip badges in the TierBadge pattern:
- Jurisdiction (Berlin/DE/EU/International) — derived from the ELI,
  surfaced on the norms list, detail header and heatmap chips/hover.
- Freshness (aktuell/geaendert/ungeprueft) — flags norms amended
  upstream (standDate + sourceSha256); renders only when stale.
- Jurist review — marks evaluations a trusted jurist has confirmed
  (optional; the figure stands on its own).
Models gain Jurisdiction/Freshness enums, Norm.freshness/supersededNote
and Evaluation.reviewedBy/reviewedAt; HubRepository parses them from
the flow bag (ELI fallback). HeatmapPage shows a real empty-state
(hub-down vs no-evaluations) instead of a blank plot, and connect()
no longer throws on a failed probe.

Signed-off-by: flemming-it <sf@flemming.it>

app/lib/widgets/heatmap_grid.dart

@@ -267,7 +267,8 @@ class _HeatmapPainter extends CustomPainter {
       );
       _drawText(
         canvas,
-        'Tier: ${e.tierLowest.short}   Klick → Detail',
+        'Bereich: ${e.norm.jurisdiction.short}   '
+            'Tier: ${e.tierLowest.short}   Klick → Detail',
         box.topLeft + const Offset(10, 44),
         const TextStyle(
           color: mute,