fix: install datajoint-python in BUILD mode for mkdocstrings

Problem:
- mkdocs build failing with: ModuleNotFoundError: No module named 'datajoint'
- mkdocstrings needs to import datajoint to generate API docs
- Previous fix only mounted source but didn't install it in BUILD mode

Solution:
- Install datajoint-python in BUILD mode with 'pip install -e'
- mkdocstrings can now import and introspect modules for API docs
- No database connectivity needed - just package installation

This completes the fix started in PR #102.

Author: dimitri-yatsenko

docker-compose.yaml

@@ -64,8 +64,9 @@ services:
             pip install scikit-image pooch
             mkdocs serve --config-file ./mkdocs.yaml -a 0.0.0.0:8000
         elif echo "$${MODE}" | grep -i build &>/dev/null; then
-            # BUILD mode: just build static site from pre-executed notebooks
-            # datajoint-python source is mounted for mkdocstrings API doc generation
+            # BUILD mode: build static site from pre-executed notebooks
+            # Install datajoint-python for mkdocstrings (needs to import for API docs)
+            pip install -e /datajoint-python
             mkdocs build --config-file ./mkdocs.yaml
         else
             echo "Unexpected mode..."