🛡️ Sentinel: [CRITICAL] Fix Path Traversal in Snapshot Command

[bitcoiner-dev]

🚨 Severity: CRITICAL
💡 Vulnerability: The snapshot command's run function directly interpolated user-supplied values (args.name) into file paths: snap_dir.join(format!("{name}.json")). Because there was no validation on the name argument, this effectively created a Path Traversal vulnerability where sequences like ../ could be used to write data or read arbitrary json data from outside the snapshot directory.
🎯 Impact: This allows arbitrary file overwrites and potential system compromise depending on what data the application attempts to read or parse from the user-controlled file location on disk.
🔧 Fix: Added a strict validation function validate_file_name to src/utils.rs that ensures file names are limited strictly to ASCII alphanumeric characters, underscores, and dashes. src/commands/snapshot.rs was updated to call this validation before processing snapshot save or restore actions.
✅ Verification: Ran cargo test and cargo clippy which passed. Validated that providing valid strings works as expected, and anything else results in an error.

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PR created automatically by Jules for task 14316805293302288970 started by @bitcoiner-dev

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