fix: generate dist/package.json with .mjs export maps post-build

Ensures bare specifier imports like 'openclaw/plugin-sdk/...' resolve
correctly without requiring a manual node_modules/openclaw symlink.

Fixes TM-3/TM-4 gateway startup failures due to ERR_MODULE_NOT_FOUND
for openclaw plugin-sdk subpath imports.

scripts/runtime-postbuild.mjs

@@ -3,6 +3,7 @@ import { copyBundledPluginMetadata } from "./copy-bundled-plugin-metadata.mjs";
 import { copyPluginSdkRootAlias } from "./copy-plugin-sdk-root-alias.mjs";
 import { stageBundledPluginRuntimeDeps } from "./stage-bundled-plugin-runtime-deps.mjs";
 import { stageBundledPluginRuntime } from "./stage-bundled-plugin-runtime.mjs";
+import { writeDistPackageJson } from "./write-dist-package-json.mjs";
 import { writeOfficialChannelCatalog } from "./write-official-channel-catalog.mjs";
 
 export function runRuntimePostBuild(params = {}) {
@@ -11,6 +12,7 @@ export function runRuntimePostBuild(params = {}) {
   writeOfficialChannelCatalog(params);
   stageBundledPluginRuntimeDeps(params);
   stageBundledPluginRuntime(params);
+  writeDistPackageJson(params);
 }
 
 if (import.meta.url === pathToFileURL(process.argv[1] ?? "").href) {

scripts/write-dist-package-json.mjs

@@ -0,0 +1,36 @@
+#!/usr/bin/env node
+// Generates dist/package.json with proper ESM export maps so that
+// bare specifier imports like "openclaw/plugin-sdk/..." resolve correctly.
+//
+// Run automatically as part of runtime-postbuild; can also be run standalone:
+//   node scripts/write-dist-package-json.mjs
+import fs from "node:fs";
+import path from "node:path";
+import { pathToFileURL } from "node:url";
+
+export function writeDistPackageJson(params = {}) {
+  const distDir = params.rootDir
+    ? path.join(params.rootDir, "dist")
+    : path.join(process.cwd(), "dist");
+
+  const pkg = {
+    name: "openclaw",
+    version: "0.0.0",
+    type: "module",
+    main: "./entry.mjs",
+    exports: {
+      ".": "./entry.mjs",
+      "./plugin-sdk": "./plugin-sdk/index.mjs",
+      "./plugin-sdk/*": "./plugin-sdk/*.mjs",
+    },
+  };
+
+  const outPath = path.join(distDir, "package.json");
+  fs.mkdirSync(distDir, { recursive: true });
+  fs.writeFileSync(outPath, JSON.stringify(pkg, null, 2) + "\n");
+  console.log(`[write-dist-package-json] Wrote ${outPath}`);
+}
+
+if (import.meta.url === pathToFileURL(process.argv[1] ?? "").href) {
+  writeDistPackageJson();
+}