Removing pip plugin since it was not used.

```
% devbox add pip

Error: Package pip not found
```

we also moved `venvShellHook.sh` to a python directory.

plugins/python.json

@@ -3,10 +3,11 @@
   "version": "0.0.4",
   "description": "Python in Devbox works best when used with a virtual environment (venv, virtualenv, etc.). Devbox will automatically create a virtual environment using `venv` for python3 projects, so you can install packages with pip as normal.\nTo activate the environment, run `. $VENV_DIR/bin/activate` or add it to the init_hook of your devbox.json\nTo change where your virtual environment is created, modify the $VENV_DIR environment variable in your init_hook",
   "env": {
-    "VENV_DIR": "{{ .DevboxProjectDir }}/.venv"
+    "VENV_DIR": "{{ .DevboxProjectDir }}/.venv",
+    "UV_PYTHON": "{{ .DevboxProjectRoot }}/.devbox/nix/profile/default/bin/python"
   },
   "create_files": {
-    "{{ .Virtenv }}/bin/venvShellHook.sh": "pip/venvShellHook.sh"
+    "{{ .Virtenv }}/bin/venvShellHook.sh": "python/venvShellHook.sh"
   },
   "shell": {
     "init_hook": ["{{ .Virtenv }}/bin/venvShellHook.sh"]