🛡️ Sentinel: [MEDIUM] Fix shell execution risk in Docker prune

[acebytes]

• 🚨 Severity: MEDIUM
• 💡 Vulnerability: Raw shell command execution using /bin/bash -c which is a bad security practice and could lead to command injection if arguments become dynamic.
• 🎯 Impact: Lower risk since it's currently hardcoded, but prevents future vulnerabilities if the command structure changes.
• 🔧 Fix: Replaced with direct Foundation.Process instantiation using string array arguments and /usr/bin/env. Both output and error streams are safely piped by assigning the identical Pipe() instance to both process.standardOutput and process.standardError.
• ✅ Verification: Tested using local ./scripts/test.sh.

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PR created automatically by Jules for task 5374790651883743909 started by @acebytes

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