fix: 🛡️ Sentinel: [HIGH] Prevent Option Injection / Arbitrary Command Execution in swapfile creation

[Hardonian]

🎯 What:
The preflight script used sudo dd, sudo mkswap, sudo chmod, and sudo swapon with a hardcoded swapfile path, but lacked explicit protection against arbitrary option injection and path traversal if the path was parameterized.

⚠️ Risk:
A malicious user or process could supply a payload mimicking command line flags (e.g. --some-option=value) or traverse directories (e.g. ../) allowing them to execute arbitrary actions as the root user. This could be abused to execute commands or overwrite crucial system files.

🛡️ Solution:

1. Created isValidSwapPath(path) to strictly validate alphanumeric names, enforcing absolute paths, and rejecting ...
2. Passed the parameterized path correctly through to the commands, and added the end-of-options -- delimiter to chmod, mkswap, swapon, swapoff and rm to disallow option injection.
3. Passed the parameterized path correctly through to the fstab regex check.

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PR created automatically by Jules for task 26154607767391731 started by @Hardonian

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