Legacy file upload

⚠ Intentionally vulnerable. This endpoint reproduces classic mistakes for agent practice — do not deploy publicly.

What's broken on purpose:

• Path traversal — the uploaded filename is used verbatim. A filename containing ../ writes outside uploads_public/.
• Weak blacklist — only .exe, .py, .sh, .php are blocked, and the check is case-sensitive. .HTML, .svg, .Php, double extensions, all pass.
• No size cap, no magic-byte sniff.
• Public serving — accepted files are served back at /files/<name>, so .html / .svg uploads enable stored XSS on subsequent fetch.

The JSON response echoes stored_path (resolved real path) so you can confirm whether a traversal escaped the upload root.