fix: move Alembic to package submodule for Docker compatibility

- Move alembic/ directory to nextcloud_mcp_server/alembic/ subpackage
- Update migrations.py to use package location instead of alembic.ini
- Update env.py to set script_location dynamically
- Update alembic.ini for development CLI usage
- Fix Dockerfile typo: .vnev -> .venv

This fixes FileNotFoundError when running in Docker with non-editable
install. The alembic package is now installed with the main package,
making it work in both development and production environments.

Resolves: Docker startup error 'alembic.ini not found at
/app/.venv/lib/python3.12/site-packages/alembic.ini'

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Dockerfile

@@ -22,7 +22,7 @@ RUN uv sync --locked --no-dev --no-editable --no-cache
 
 ENV PYTHONUNBUFFERED=1
 ENV VIRTUAL_ENV=/app/.venv
-ENV PATH=/app/.vnev/bin:$PATH
+ENV PATH=/app/.venv/bin:$PATH
 ENV TESSDATA_PREFIX=/usr/share/tesseract-ocr/5/tessdata
 
 ENTRYPOINT ["/app/.venv/bin/nextcloud-mcp-server", "run", "--host", "0.0.0.0"]