fix(devops): add post-commit auto-heal for stash-pop conflicts (#2416)

[mrveiss]

Closes #2416

Summary

• Added scripts/hooks/post-commit that detects conflict markers left by pre-commit stash/pop
• Automatically restores files from HEAD when conflicts detected
• Added install-post-commit entry in .pre-commit-config.yaml (mirrors existing install-post-checkout pattern)

Test plan

• Script passes bash -n syntax check
• install-post-commit hook runs successfully during commit
• No-op when no conflicts exist

[github-actions]

✅ SSOT Configuration Compliance: Passing

🎉 No hardcoded values detected that have SSOT config equivalents!