feat(lab3): SSH signing, gitleaks and history rewrite

[MikeNovikoff]

Goal

Configure SSH commit signing, wire gitleaks into a pre-commit hook to prevent secret leaks, and practice history rewriting using git filter-repo.

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Changes

• Configured global Git to use ed25519 SSH key for commit signing (commit.gpgsign true).
• Added .pre-commit-config.yaml with gitleaks, detect-private-key, and check-added-large-files hooks.
• Added submissions/lab3.md with full documentation, STRIDE-R reflections, and bonus task proof.
• Added submissions/e3/verified.png demonstrating the GitHub Verified badge.

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Testing

• SSH Signing: Verified locally via git log --show-signature -1 and confirmed the green "Verified" badge on GitHub.
• Pre-commit: Planted a fake GH_PAT in leak-attempt.txt; gitleaks successfully intercepted and aborted the commit (exit code 1).
• History Rewrite (Bonus): Successfully purged a planted token from a sandbox repo using git filter-repo --replace-text with the --force flag, reducing the secret grep count from 2 to 0.

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Artifacts

• Lab Report
• Verified Badge Screenshot

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Checklist

• Title is clear (feat(lab3): SSH signing, gitleaks and history rewrite)
• No secrets/large temp files committed
• submissions/lab3.md exists

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Personal Notes

Configured on Windows using Git Bash. Handled CRLF/LF line ending conversions and successfully bypassed filter-repo fresh clone restrictions using --force during the sandbox test. All secrets in the report are properly redacted to prevent CI hook failures.