feat(tests): add Validated Tests as dedicated page, remove duplicate sidebar entry

- New /tests/validated page with its own route and sidebar link, showing
  only validated tests with Attack and Detection result badges.
- Removed the duplicate "My Pending Tasks" sidebar entry (same as All Tests).
- All Tests table no longer shows validated tests; clicking the Validated
  counter card navigates to the new page instead.
- Validated option removed from the state filter dropdown in All Tests.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/Sidebar.tsx

@@ -10,7 +10,7 @@ import {
   FileText,
   ChevronDown,
   ListChecks,
-  ClipboardList,
+  CheckCircle,
   Database,
   Crosshair,
   Zap,
@@ -41,7 +41,7 @@ const mainLinks: NavItem[] = [
     icon: FlaskConical,
     children: [
       { to: "/tests", label: "All Tests", icon: ListChecks },
-      { to: "/tests?view=pending", label: "My Pending Tasks", icon: ClipboardList },
+      { to: "/tests/validated", label: "Validated Tests", icon: CheckCircle },
       { to: "/test-catalog", label: "Test Catalog", icon: BookOpen },
     ],
   },