build: install package itself to ensure all dependencies are installed

Dockerfile

@@ -35,6 +35,9 @@ RUN pip install --no-cache-dir --upgrade pip && \
 # Copy the rest of the application
 COPY . .
 
+# Install the package itself to ensure all dependencies (e.g. cryptography) from pyproject.toml are installed
+RUN pip install .
+
 # Copy built frontend assets from Stage 1
 COPY --from=build-frontend /app/web_client/dist /app/web_client/dist