Cannot find installed Python packages

I'm new to Python, so I hope my environment is setup correctly - I followed instructions carefully.

I'm using Poetry - here is `pyproject.toml` in my Deno project root:
```
[tool.poetry]
name = "engine"
version = "0.1.0"
description = ""
authors = ["Your Name "]
readme = "README.md"

[tool.poetry.dependencies]
python = "^3.13"
graphiti-core = "^0.3.9"

[build-system]
requires = ["poetry-core"]
build-backend = "poetry.core.masonry.api"
```

I've added the dependency. If I do it again like so, it seems to confirm that:
```
❯ poetry add graphiti-core@latest
Using version ^0.3.9 for graphiti-core

Updating dependencies
Resolving dependencies... (0.1s)

No dependencies to install or update
```

I'm also exporting `DENO_PYTHON_PATH` as per instructions:
```
export DENO_PYTHON_PATH="/opt/homebrew/Cellar/python@3.13/3.13.0_1/Frameworks/Python.framework/Versions/3.13/lib/libpython3.13.dylib"
```

But when I run my Deno entry point, I get this error:
```
❯ deno task ws 
Task ws deno run --allow-read --allow-write --allow-env --allow-net --allow-ffi --unstable src/ws.ts
error: Uncaught (in promise) PythonError: No module named 'graphiti_core'
```

What am I doing wrong?