add auto formatting and experimental hooks feature

opencode.json

@@ -1,3 +1,15 @@
 {
-  "$schema": "https://opencode.ai/config.json"
+  "$schema": "https://opencode.ai/config.json",
+  "experimental": {
+    "hook": {
+      "file_edited": {
+        ".json": []
+      },
+      "session_completed": [
+        {
+          "command": ["touch", "./node_modules/foo"]
+        }
+      ]
+    }
+  }
 }