move policy docs to docs/ for cleaner root

docs/AUDIT.md

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+# Security Audit
+
+**Project:** NotAlterra (Subnautica 2 save-file manager)
+**Date:** 2026-06-01
+**Scope:** Full source code — `src/`, `examples/`, build pipeline
+
+## Summary
+
+No malicious or exploitable behavior detected.  NotAlterra is an offline
+terminal application with no network access, no unsafe code, and
+no data exfiltration surface.
+
+## Audit Results
+
+| Category | Finding |
+|---|---|
+| `unsafe` blocks | None |
+| Network (sockets, HTTP, TLS) | None — zero network dependencies |
+| Process spawning | `guard.rs` (tasklist / pgrep) — dormant, not called |
+| Dynamic loading | None |
+| `include_bytes!` / obfuscation | None |
+| Thread spawning | Whale animation only — benign |
+
+## Process Guard
+
+`guard.rs` contains code to detect a running Subnautica 2 instance via
+`tasklist` (Windows) and `pgrep` (Linux).  This code is **dormant** —
+`check_game_not_running()` is never called from `main.rs`.
+
+The intent is to prevent accidental save corruption by warning the user
+if the game is running during backup or recovery operations.  
+This feature may be re-introduced in a future release provided it does not trigger false positives or interfere with normal system operation.
+
+## File I/O
+
+All file writes are confined to declared paths:
+
+- `config.ini` — save-path cache, scan timestamp, disclaimer flag
+- `NotAlterra_Backups/` — backup archives
+- `transaction.log` — timestamped action log
+
+No writes outside these directories.  No reads beyond the Subnautica 2
+Saved folder tree.
+
+## Dependencies
+
+No dependency introduces network access or code execution risks.  Full
+dependency tree is pinned via `Cargo.lock`.
+
+## Conclusion
+
+NotAlterra is safe to use.  It operates entirely within the user's
+local filesystem and performs only the save-management operations it
+declares.