Add enroot import validation for launch scripts in PR review

[Klaud-Cold]

Summary

• Add PR review validation to warn when runners/launch_*.sh scripts don't transform public Docker images to enroot local images
• The validation checks for the enroot import -o $SQUASH_FILE docker://$IMAGE pattern
• Issues a 🟡 WARNING (not blocking) when the pattern is missing, prompting the developer to either add the pattern or explain why it's intentionally omitted

Why this matters

• Ensures the exact same public NGC/Docker Hub image is used
• Makes benchmarks reproducible by anyone with access to the public image
• Prevents reliance on pre-existing local container images that others cannot access

Test plan

• Verify PR review workflow triggers on launch script changes
• Check that the validation correctly identifies scripts with enroot import patterns
• Confirm the warning message is helpful and actionable

🤖 Generated with Claude Code

Triggered from: https://github.com/InferenceMAX/InferenceMAX/pull/588#discussion_r2739397836