#30 共通から外すとこだけ

frontend/src/App.tsx

@@ -69,7 +69,11 @@ const App = () => {
           <div className="flex flex-col h-screen w-screen">
             <TopNav user={user} setUser={setUser} />
             <div className="flex flex-1">
-              <TagSidebar posts={posts} setPosts={setPosts} />
+              <Routes>
+                <Route path="/posts/new" />
+                <Route path="/posts" element={<TagSidebar posts={posts} setPosts={setPosts} />} />
+                <Route path="/posts/:id" element={<TagSidebar posts={posts} setPosts={setPosts} />} />
+              </Routes>
               <main className="flex-1 overflow-y-auto p-4">
                 <Routes>
                   <Route path="/" element={<Navigate to="/posts" replace />} />