feat(web): DiffView + DomainDiffPage с prune-guard по умолчанию выключенным

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwxdSt4reTm7Dj1oxRvpP3

web/src/App.tsx

@@ -1,5 +1,6 @@
 import { Routes, Route, Navigate } from "react-router-dom"
 import { Layout } from "@/components/Layout"
+import { DomainDiffPage } from "@/pages/DomainDiffPage"
 
 function Placeholder({ name }: { name: string }) {
   return <div className="p-8 text-2xl">{name}</div>
@@ -11,7 +12,7 @@ export function App() {
       <Routes>
         <Route path="/" element={<Navigate to="/domains" replace />} />
         <Route path="/domains" element={<Placeholder name="Domains" />} />
-        <Route path="/domains/:id" element={<Placeholder name="Domain diff" />} />
+        <Route path="/domains/:id" element={<DomainDiffPage />} />
         <Route path="/accounts" element={<Placeholder name="Accounts" />} />
         <Route path="/templates" element={<Placeholder name="Templates" />} />
       </Routes>