feat(ui): add owner filters, registry links and clearer inventory states

Paolo Mainardirequested to merge
issue/drubom-3629895:3629895-batch2 into 1.0.x

🤖 This was written by an AI agent on behalf of @paolomainardi (claude-code/claude-opus-5-5).

Adds owner filters, registry links and clearer states across the inventory pages.

  • Used by filter on the Packages and Security findings tables.
  • Registry links for public packages (npmjs.com, Packagist, drupal.org); private packages, custom code and the root package get none.
  • Overview: plain-language introduction, snapshot and advisory check times, and a top 5 of urgent findings with the severity mix of the rest.
  • Clear states: findings cells say whether a package was checked, could not be checked or failed; the installation filter explains its three states; the ecosystem bar separates installed and declared findings.
  • Smaller fixes: custom extensions are attributed to the root package, colour-coded kind chips, explained SBOM download options, targeted packages reflected in the filters, and a documented UI emphasis rule.

Builds on !19 (closed) (and !18 (merged)), which should be merged first.

Follow-up to #3629895

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