🛡️ Sentinel: [security improvement] Refactor dockerPrune to avoid /bin/bash shell wrapper

[acebytes]

🛡️ Sentinel: [security improvement]

💡 Vulnerability: The dockerPrune method was executing docker system prune via /bin/bash -c "docker system prune -f 2>&1". While the string itself is hardcoded, relying on shell wrappers (bash -c) inherently violates the principle of least privilege, as it invokes a full shell interpreter environment which theoretically broadens the attack surface for command injection if variables were later introduced.
🎯 Impact: Using a shell interpreter is an anti-pattern. If future modifications interpolated variables, it could result in command injection. Eliminating the shell removes the class of vulnerability altogether (defense-in-depth).
🔧 Fix: Refactored the dockerPrune implementation in Sources/Cacheout/ViewModels/CacheoutViewModel.swift to invoke docker directly via /usr/bin/env docker system prune -f using explicit Process arguments. Native Swift Pipe() redirection securely replaces 2>&1 by mapping the same pipe reference to both standardOutput and standardError.
✅ Verification: Verified by code review. The standard output and standard error will successfully stream to the same pipe object, replicating the 2>&1 behavior natively without a shell interpreter, and ensuring that any downstream parsing logic operates uninterrupted.

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PR created automatically by Jules for task 17698090583016688259 started by @acebytes

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