🛡️ Sentinel: [HIGH] Fix untrusted code execution via git config

[tachyon-beep]

🚨 Severity: HIGH
💡 Vulnerability: Potential untrusted local code execution via malicious .git/config files (e.g. core.fsmonitor) when invoking git subprocess commands in src/wardline/core/delta.py and src/wardline/core/legis.py.
🎯 Impact: An attacker could execute arbitrary code by placing a malicious .git/config in a directory scanned by Wardline.
🔧 Fix: Added _SAFE_GIT_CONFIG = ("-c", "core.fsmonitor=false") to all git subprocess calls in delta.py and legis.py, aligning with the existing mitigation found in attest.py and attest_key.py. Fixed tests to expect the new arguments.
✅ Verification: Ran make test, all unit tests pass including the patched test_delta.py.

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PR created automatically by Jules for task 1566641735470158710 started by @tachyon-beep

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