docs: add security policy

Author: edouard-claude

SECURITY.md

@@ -0,0 +1,16 @@
+# Security Policy
+
+## Supported Versions
+
+| Version | Supported |
+|---------|-----------|
+| latest  | ✅        |
+| < latest | ❌       |
+
+## Reporting a Vulnerability
+
+If you discover a security vulnerability, please report it via [GitHub Security Advisories](https://github.com/edouard-claude/snip/security/advisories/new).
+
+**Do not open a public issue.**
+
+You can expect an initial response within 72 hours.