🔒 fix: replace vulnerable echo with safe printf in post-deploy-health.sh

[sstklen]

🎯 What: Replaced echo "$CMD" with printf '%s\n' "$CMD" in hooks/post-deploy-health.sh.
⚠️ Risk: The vulnerability allowed unintended interpretation of command line options. For example, inputs starting with a hyphen (like -e or -n) were mistakenly interpreted as a flag by echo, which could lead to security issues or break the hook functionality.
🛡️ Solution: printf '%s\n' safely handles all string inputs without unintended option interpretation, ensuring the script behaves robustly when checking deploy commands.

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PR created automatically by Jules for task 13417404026007461502 started by @sstklen

[google-labs-jules]

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