fix: handle StaticSitesClient stderr and non-zero exit codes

The deploy command silently ignored failures from the StaticSitesClient
binary. When the binary crashed (e.g., missing native dependencies on
slim Docker images), the CLI reported success and exited with code 0.

This fix:
- Adds stderr handler to capture binary error output
- Adds else branch for non-zero exit codes with diagnostic message
- Calls process.exit(1) on failure so CI/CD detects it

Fixes #536, #594
Refs: ICM 21000000909499

Author: LongOddCode

src/cli/commands/deploy/deploy.ts

@@ -315,6 +315,13 @@ export async function deploy(options: SWACLIConfig) {
           });
       });
 
+      child.stderr!.on("data", (data) => {
+        const stderrOutput = data.toString().trim();
+        if (stderrOutput) {
+          logger.error(stderrOutput);
+        }
+      });
+
       child.on("error", (error) => {
         logger.error(error.toString());
       });
@@ -325,6 +332,12 @@ export async function deploy(options: SWACLIConfig) {
         if (code === 0) {
           spinner.succeed(chalk.green(`Project deployed to ${chalk.underline(projectUrl)} 🚀`));
           logger.log(``);
+        } else {
+          spinner.fail(chalk.red(`Deployment failed with exit code ${code}`));
+          logger.error(`The deployment binary exited with code ${code}.`);
+          logger.error(`If you are running in a minimal container image, ensure native dependencies are installed.`);
+          logger.error(`Run ${chalk.cyan(`ldd ${binary}`)} to check for missing shared libraries.`);
+          process.exit(1);
         }
       });
     }