FindContainerImages does not detect images in initContainers and CronJob jobTemplate

Title

FindContainerImages does not detect images in initContainers and CronJob jobTemplate

Description

Summary

The current implementation of FindContainerImages only extracts container images from:
spec.template.spec.containers.image

However, Kubernetes manifests can reference container images in additional valid fields which are currently not handled.

Missing Fields

The function does not detect images from:
spec.template.spec.initContainers.image
spec.jobTemplate.spec.template.spec.containers.image (CronJob)
spec.jobTemplate.spec.template.spec.initContainers.image (CronJob)
There is already a TODO comment in the code mentioning this limitation.

Impact

Because of this limitation:
Images used in initContainers are ignored.
CronJob images may not be detected.
Image tracking or diff logic relying on this function may be incomplete.
Manifest analysis becomes inaccurate for certain workloads.

Suggested Improvement

Extend FindContainerImages to also extract images from:
spec.template.spec.initContainers.image
spec.jobTemplate.spec.template.spec.containers.image
spec.jobTemplate.spec.template.spec.initContainers.image

This can be implemented using the existing nestedStringSlice helper for consistency.

Start at FindContainerImages and inspect the existing TODO and nestedStringSlice helper. Trace how images are collected from the current template path, then extend the collection to the listed initContainers and CronJob jobTemplate paths. Done means all four valid image locations are detected consistently.