readme.md links to non-existent security.md

PR #610 updated readme.md to link to security.md:

```
3. Security Issues should be handled as per our [security.md](security.md)
```

But the file doesn't exist:

<img width="1289" height="1029" alt="Image" src="https://github.com/user-attachments/assets/2e778961-e6e6-4bbb-afbd-2a1fecd45d5a" />