feat: initial corvid — standalone ticket service extracted from homelab-dashboard

Extracts the ticket/attachment system into a reusable pip-installable package.
Centralises homelab MCP server (tickets, attachments, system logs) here.

- corvid package: models, router (make_router factory), config, standalone main
- Alembic migration chain for fresh standalone deployments
- Docker Compose for standalone deployment (port 8090)
- mcp_server.py: moved from homelab-dashboard, CORVID_REPO_PATH configurable

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,14 @@
+FROM python:3.12-slim
+
+WORKDIR /app
+COPY pyproject.toml .
+RUN pip install --no-cache-dir -e ".[mcp]"
+
+COPY alembic.ini .
+COPY alembic/ alembic/
+COPY corvid/ corvid/
+COPY entrypoint.sh .
+RUN chmod +x entrypoint.sh
+
+EXPOSE 8080
+CMD ["./entrypoint.sh"]