feat(frontend): Batches browser page with list + detail drawer

src/components/Sidebar.tsx

@@ -3,6 +3,7 @@ import {
   Activity,
   CheckCircle2,
   GitMerge,
+  Layers,
   LayoutDashboard,
   Receipt,
   Stethoscope,
@@ -116,6 +117,22 @@ export function Sidebar() {
               <span>999 ACKs</span>
             </NavLink>
           </li>
+          <li>
+            <NavLink
+              to="/batches"
+              className={({ isActive }) =>
+                cn(
+                  "group relative flex items-center gap-3 rounded-md px-3 py-2 text-sm font-medium transition-colors",
+                  isActive
+                    ? "nav-active"
+                    : "text-muted-foreground hover:text-foreground hover:bg-muted/40"
+                )
+              }
+            >
+              <Layers className="h-4 w-4" strokeWidth={1.5} />
+              <span>Batches</span>
+            </NavLink>
+          </li>
         </ul>
       </nav>