fix: avoid premature tmp cleanup for multi-container scans

[mdusher]

Description

When running trivy-operator in ClientServer mode, ScanJobs will fail due to the temp directory being cleaned up by another container's scan. This causes VulnerabilityReports to either not be generated, or delayed until you are lucky enough for all containers to complete their image scans before a cleanup occurs.

This pull request is based on the patch @daanschipper mentioned in the original issue (daanschipper@1749113) to use per-container tmp volumes when running scans to avoid the premature temp file cleanup.

Related issues

• Close ScanJobs fail in Trivy Operator Server Mode — all ScanJob pods in Error state, no vulnerabilities detected #2815

Checklist

• I've read the guidelines for contributing to this repository.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
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