fix: resolve build errors in pass_mgr, pcexec, and safe-restart

- Fix Go syntax error: use BoolVar for --username flag instead of string
- Fix TypeScript type errors: filter undefined values from process.env
- Fix TypeScript type error: add type assertion for fetch response
- Add .gitignore to exclude node_modules and build outputs

safe-restart/src/safe-restart.ts

@@ -73,7 +73,7 @@ export async function safeRestart(options: SafeRestartOptions): Promise<SafeRest
           }),
         });
 
-        const data = await response.json();
+        const data = await response.json() as { status: string };
 
         if (data.status === 'OK') {
           log('All agents ready for restart');