Fix PocketGen Colab Setup

I’ve been following the official PocketGen notebook but the run breaks when it tries to locate the PocketGen directory:

```
FileNotFoundError: print(f"Directory not found: {pocketgen_dir}")
```

Google Drive is already mounted in the session, so the problem appears to be a configuration issue rather than a mounting error. I need a clean, reproducible Colab notebook that:

• locates or correctly creates the PocketGen folder inside my mounted Drive
• installs every required dependency without version clashes
• runs the demo cell(s) end-to-end without raising runtime or path errors

Please patch the current notebook (or build a fresh one) and walk me through any Drive path variables you adjust so I can repeat the process later. A quick video or concise written steps at the end will be enough for documentation.