Add browser Python editor with Pyodide, user auth, and workspace API

- FastAPI serves static UI, file CRUD under code/ and read-only lib/
- Pyodide worker runs Python and Jedi completions in the browser
- SQLite accounts: login/register, session cookies, superuser user management
- Optional EDITOR_API_KEY, AUTH_* env vars, .env.example
- Pipenv, pytest, Selenium smoke test, README

Made-with: Cursor

workspace/lib/helpers.py

@@ -0,0 +1,5 @@
+"""Shared helpers (read-only on server; copied into Pyodide when you run)."""
+
+
+def greet(name: str) -> str:
+    return f"Hello, {name}!"