fix(enhanced): add runtime safety checks to prevent errors

- Add typeof check for oldStartup function in EmbedFederationRuntimeModule
- Add typeof check for __webpack_require__.x in StartupHelpers

These defensive checks prevent runtime errors when expected functions
don't exist in certain build configurations.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ScriptedAlchemy

packages/enhanced/src/lib/container/runtime/EmbedFederationRuntimeModule.ts

@@ -71,7 +71,9 @@ class EmbedFederationRuntimeModule extends RuntimeModule {
           `  hasRun = true;`,
           `  ${initRuntimeModuleGetter};`,
           `}`,
-          `return oldStartup();`,
+          `if (typeof oldStartup === 'function') {`,
+          `  return oldStartup();`,
+          `}`,
         ],
       )};`,
     ]);

packages/enhanced/src/lib/startup/StartupHelpers.ts

@@ -49,7 +49,7 @@ export const generateEntryStartup = (
     '',
     '\n',
     'var promises = [];',
-    '__webpack_require__.x();',
+    'if (typeof __webpack_require__.x === "function") __webpack_require__.x();',
   ];
 
   const treeRuntimeRequirements = chunkGraph.getTreeRuntimeRequirements(chunk);