add `opencode.json`

opencode.json

@@ -0,0 +1,15 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "theme": "opencode",
+  "model": "google/gemini-2.5-flash-preview-05-20",
+  "mode": {
+    "build": {
+      "model": "moonshotai/kimi-k2"
+    },
+    "plan": {
+      "model": "anthropic/claude-4-sonnet-20250522"
+    }
+  },
+  "share": "disabled",
+  "autoupdate": true
+}