Is your feature request related to a problem?

I'm using npm autodiscovery with a custom .npmrc file for a private registry. The npm resource plugin supports npmrcpath, url, and registrytoken fields, but there's no way to set these at the autodiscovery level.

After autodiscovery generates manifests, I have to manually edit each one to add these fields.

Solution you'd like

Allow setting resource-specific config at the autodiscovery level that propagates to all generated manifests:

autodiscovery:
  crawlers:
    npm:
      rootdir: "."
      npmrcpath: "/custom/.npmrc"
      url: "https://npm.example.com"
      registrytoken: "${NPM_TOKEN}"

Implementation would add these fields to the autodiscovery plugin's Spec struct and pass them through manifest templates (similar to how scmid/actionid already work).

Alternatives you've considered

Checked if a generic engine-level solution exists - it doesn't, and building one seems like over-engineering for the ~8 plugins that would need this.

Per-plugin implementation seems more practical and type-safe.

Anything else?

Gap analysis of all 20 autodiscovery plugins shows:

High priority (5 plugins - share identical auth pattern):

• dockerfile, kubernetes, dockercompose, nomad, ko - all need docker registry credentials (username/password/token)

Medium priority (4 plugins):

• npm - needs npmrcpath/url/registrytoken
• cargo - needs registry auth config
• helm, argocd, fleet, flux - need OCI/chart repo tokens

No need (11 plugins): golang, maven, terraform, etc - public sources

The 5 docker-based plugins could share a common ContainerRegistryAuth struct since they generate identical resource types.

Could be implemented incrementally as needed.