build: fix nx config (#2824)

nx.json

@@ -29,7 +29,7 @@
         "{projectRoot}/build",
         "{projectRoot}/out",
         "{projectRoot}/node_modules/.cache",
-        "apps/web/.next/cache",
+        "apps/web/.next",
         "packages/storybook/storybook-static",
         "packages/native/affine.*.node"
       ],
@@ -83,6 +83,9 @@
         }
       ]
     },
+    "export": {
+      "dependsOn": ["build"]
+    },
     "dev": {
       "dependsOn": ["^build"]
     },