feat(precedents): surface auto-detected incoming citations in the "ציטוטים מקושרים" panel

The precedent-detail "ציטוטים מקושרים" panel rendered only MANUAL appeal-chain
links (case_law_relations), so it stayed empty even when decisions cite the
ruling — the automatic citation graph (precedent_internal_citations) was never
surfaced. e.g. עע"מ 317/10 (שפר) has 12 incoming citations in the DB, none shown.

Fills the existing panel from the citation graph (data/logic only, no new
visual design — gate-exempt per web-ui/AGENTS.md):
- citation_extractor.list_citations_to_case_law: return source precedent_level/
  court/date too (additive; reuses the one canonical incoming query — G2).
- precedent_library.get_precedent: add incoming_citations[], shaped like the
  RelatedCase row. No parallel resolution path.
- web-ui: render incoming citations in the same row style, read-only (no unlink),
  de-duped against manual links; manual "קשר" linking preserved alongside.

Invariants: G2 (single citation-resolution path, reused), G1 (graph self-heals
via existing relink_orphan_citations on upload). No schema change.

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

web-ui/src/app/precedents/[id]/page.tsx

@@ -236,7 +236,11 @@ export default function PrecedentDetailPage({
 
           {/* side rail — citations + corroboration */}
           <div className="space-y-4">
-            <RelatedCasesSection caseId={id} related={data.related_cases ?? []} />
+            <RelatedCasesSection
+              caseId={id}
+              related={data.related_cases ?? []}
+              incoming={data.incoming_citations ?? []}
+            />
           </div>
         </div>
       </div>