fix(sandbox): remove ./sandbox export and build — native plugins use entrypoint directly

The sandbox entry cannot be made isolate-safe: keeping emdash external leaves an
unresolvable peer dep in the isolate; bundling it pulls in node:crypto, node:module,
and virtual:emdash/* which are equally unavailable. The export is unused — native
plugins are loaded via the descriptor entrypoint, not ./sandbox.

Author: Jmosier69

package.json

@@ -15,9 +15,6 @@
     "./admin": {
       "types": "./dist/admin.d.mts",
       "import": "./dist/admin.mjs"
-    },
-    "./sandbox": {
-      "import": "./dist/sandbox-entry.mjs"
     }
   },
   "files": [

tsdown.config.ts

@@ -26,13 +26,4 @@ export default defineConfig([
     external: ['react', 'react/jsx-runtime', 'react-dom', 'emdash', /^@emdash-cms\//],
     outDir: 'dist',
   },
-  // Sandbox entry — fully self-contained ES module for Cloudflare Worker Loader
-  // No external imports; everything must be inlined for the isolate.
-  {
-    entry: { 'sandbox-entry': 'src/index.ts' },
-    format: 'esm',
-    dts: false,
-    noExternal: [/.*/],
-    outDir: 'dist',
-  },
 ]);