Initial commit: StackPilot Phase 1 (Core)

Self-hosted Docker Compose manager.
- Backend: FastAPI + docker-py + SQLite (JWT auth, file-first stacks,
  lifecycle, live status, WebSocket logs, docker-run converter, audit log)
- Frontend: React + Vite + Tailwind (login/setup, dashboard, stacks,
  stack detail, Monaco editor, dark/light theme)
- Deployment: docker-compose.yml, Dockerfiles, nginx reverse proxy

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/Dockerfile

@@ -0,0 +1,30 @@
+FROM python:3.12-slim
+
+# Docker CLI + compose plugin are required for lifecycle commands.
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends ca-certificates curl gnupg \
+    && install -m 0755 -d /etc/apt/keyrings \
+    && curl -fsSL https://download.docker.com/linux/debian/gpg -o /etc/apt/keyrings/docker.asc \
+    && chmod a+r /etc/apt/keyrings/docker.asc \
+    && echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/debian $(. /etc/os-release && echo $VERSION_CODENAME) stable" > /etc/apt/sources.list.d/docker.list \
+    && apt-get update \
+    && apt-get install -y --no-install-recommends docker-ce-cli docker-compose-plugin \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY . .
+
+ENV STACKS_DIR=/opt/stacks \
+    DATA_DIR=/data \
+    PORT=5008
+
+EXPOSE 5008
+
+HEALTHCHECK --interval=30s --timeout=5s --start-period=10s \
+    CMD curl -fsS http://localhost:5008/api/health || exit 1
+
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "5008"]