fix: annotate pods with resolved OvercommitClass

[enriqueavindi]

Summary

Fixs #47

Use the actual OvercommitClass resolved from pod, namespace, or default
selection when setting the applied annotation, events, and mutation metrics.

This fixes namespace-labeled pods intercepted by the default webhook being
annotated with the default class instead of the class used for request
calculation.

Checklist

• Commits are signed (git commit -S)
• Commit messages follow Conventional Commits
• Documentation has been updated (if needed)
• I have read and agree to the project’s Code of Conduct
• I have signed the Contributor License Agreement (CLA)

Changes

• Propagate the resolved OvercommitClass name through the mutation flow.
• Use the resolved class for:
  • overcommit.inditex.dev/applied
  • mutation events
  • mutation metrics
• Avoid counting detailed pod mutation metrics when class resolution falls back to a no-op.
• Add a focused KUTTL e2e case for namespace-label class resolution.