refactor: codebase hardening and safe concurrency execution

[Cylae]

• Enforced explicit absolute paths for all system binaries (/usr/bin/docker, /usr/sbin/ufw, etc.) across core/ops.rs, core/system.rs, core/firewall.rs, and interface/cli.rs to mitigate $PATH substitution vulnerabilities.
• Replaced dangerous std::fs::write of sensitive configuration states in interface/cli.rs with safe atomic_write_str.
• Rewrote implicit/silent thread .unwrap() behaviors throughout production streams to surface underlying application logic errors explicitly.
• Fixed non-Unix OS system lock degradation.
• Validated modifications thoroughly against strict internal CI and testing requirements.

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PR created automatically by Jules for task 12882749818120826383 started by @Cylae

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