refactor(httpapi): fork server startup by flag (#24799)

packages/sdk/js/script/build.ts

@@ -9,7 +9,14 @@ import path from "path"
 
 import { createClient } from "@hey-api/openapi-ts"
 
-await $`bun dev generate > ${dir}/openapi.json`.cwd(path.resolve(dir, "../../opencode"))
+const openapiSource = process.env.OPENCODE_SDK_OPENAPI === "httpapi" ? "httpapi" : "hono"
+const opencode = path.resolve(dir, "../../opencode")
+
+if (openapiSource === "httpapi") {
+  await $`bun dev generate --httpapi > ${dir}/openapi.json`.cwd(opencode)
+} else {
+  await $`bun dev generate > ${dir}/openapi.json`.cwd(opencode)
+}
 
 await createClient({
   input: "./openapi.json",