feat(phase-30): add coverage snapshots, temporal comparison and auto re-testing (T-230 to T-232)

frontend/src/components/Sidebar.tsx

@@ -18,6 +18,7 @@ import {
   Grid3X3,
   Gauge,
   ShieldCheck,
+  GitCompareArrows,
 } from "lucide-react";
 import { useAuth } from "../context/AuthContext";
 
@@ -46,6 +47,7 @@ const mainLinks: NavItem[] = [
   { to: "/reports", label: "Reports", icon: BarChart3 },
   { to: "/threat-actors", label: "Threat Actors", icon: Crosshair },
   { to: "/campaigns", label: "Campaigns", icon: Zap },
+  { to: "/comparison", label: "Comparison", icon: GitCompareArrows },
   { to: "/compliance", label: "Compliance", icon: ShieldCheck },
 ];