feat(web-ui): expose citation-corroboration badge on halachot (X11)

- db.list_halachot: aggregate corroboration_count (distinct positive sources)
  + corroboration_negative from halacha_citation_corroboration (LEFT JOIN)
- web-ui: CorroborationBadge — 'מתוקף · N ציטוטים' at ≥2 (gold), soft single
  citation, danger badge on negative treatment; native title tooltips
- shown in ExtractedHalachotSection (per-precedent) + halacha review panel

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-ui/src/components/precedents/halacha-review-panel.tsx

@@ -7,6 +7,7 @@ import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { Skeleton } from "@/components/ui/skeleton";
 import { Textarea } from "@/components/ui/textarea";
+import { CorroborationBadge } from "./corroboration-badge";
 import { practiceAreaLabel } from "./practice-area";
 import {
   useHalachotPending, useUpdateHalacha, type Halacha,
@@ -115,6 +116,7 @@ function HalachaCard({
           <Badge variant="outline" className="text-[0.65rem]">
             {ruleTypeLabel(h.rule_type)}
           </Badge>
+          <CorroborationBadge halacha={h} />
         </span>
       </div>