Fix nil provider crash when purging unconfigured EC2 resources

[smahima27]

Problem

When a provider (e.g., EC2) is listed under :providers in config but is not initialized in $providers (missing credentials, not fully configured, etc.), purge_vms_and_resources crashes with:

[!] failed while purging provider ec2 VMs and folders with an error: undefined method `provider_config' for nil:NilClass

This error was observed in production logs on startup when purge_unconfigured_resources runs for the EC2 provider.

Fix

Add a nil guard in purge_vms_and_resources: if $providers[provider_name] is nil, log and return early instead of raising NoMethodError.

unless provider
  $logger.log('d', "[!] [purge] Skipping provider '#{provider_name}': not initialized")
  return
end

Testing

• Existing specs pass
• Reproduces: configure an EC2 provider in :providers without initializing it in $providers; before this fix it crashes, after this fix it logs and skips cleanly