fix: include schema in converted toml config

packages/opencode/src/config/config.ts

@@ -150,6 +150,7 @@ export namespace Config {
       .then(async (mod) => {
         const { provider, model, ...rest } = mod.default
         if (provider && model) result.model = `${provider}/${model}`
+        result["$schema"] = "https://opencode.ai/config.json"
         result = mergeDeep(result, rest)
         await Bun.write(
           path.join(Global.Path.config, "config.json"),