[Bug] check Command silently succeeds when required tool is missing false positive in dependency check

[zakaziko86]

Bug Description

checkCommand in src/lib/clients/system.ts (lines 8-16) silently succeeds
when a required binary (e.g., docker) is not installed.

Root Cause

When a binary is missing, child_process.exec throws an error with
error.code = 'ENOENT' but error.stderr is empty or undefined.
The guard if (error.stderr) evaluates to false, so the error is
swallowed and the function resolves successfully.

Impact

SimulatorService.checkInstallRequirements() sets requirementsInstalled.docker = true
even when Docker is not installed. The subsequent docker.ping() then fails
with a cryptic error instead of a clear "Docker is not installed" message.

Steps to Reproduce

1. Uninstall Docker completely
2. Run genlayer up
3. Observe: CLI proceeds as if Docker is available, then crashes with
   confusing errors instead of "Docker is not installed"

Expected Behavior

CLI should immediately show: "Docker is not installed. Please install Docker first."

Suggested Fix

} catch (error: any) {
  if (error.code === 'ENOENT' || error.stderr) {
    throw new MissingRequirementError(toolName);
  }
}

Environment

• File: src/lib/clients/system.ts lines 8-16
• Severity: Critical
• Already reported: No