scripts: 🛡️ Sentinel: [CRITICAL] Fix command injection in timestamp.pl

[ManupaKDU]

🚨 Severity: CRITICAL
💡 Vulnerability: Command injection in scripts/timestamp.pl via the -x argument. The -x argument value is passed directly to the shell without proper escaping of single quotes, allowing arbitrary command execution.
🎯 Impact: An attacker or a maliciously crafted build configuration could execute arbitrary shell commands during the build process, potentially compromising the build environment.
🔧 Fix: Escaped single quotes (s/'/'\''/g) in the -x argument before passing it to the find command in the shell.
✅ Verification: Tested the script with a payload (-x "'; id > /tmp/id_out; echo '") to ensure the command is no longer executed. Run make help to verify no regressions.

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PR created automatically by Jules for task 11775547999796302198 started by @manupawickramasinghe

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