Scaffold FastAPI backend skeleton with health probes

Phase 0 foundation. uv-managed FastAPI app (package=false, runs from source via uv run). Layered seams in place: app/api for routers, app/core for config (pydantic-settings, fully env-driven) and the async SQLAlchemy engine; service/repository/domain layers land with the data model.

Exposes /health (liveness) and /health/ready (Postgres reachability via SELECT 1, 503 on failure) so the deploy wiring is verifiable before any data model exists. Includes a liveness test and the resolved uv.lock. Ignore pytest/ruff/mypy caches.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Justin Paul <justin@jpaul.me>

backend/Dockerfile

@@ -0,0 +1,25 @@
+# syntax=docker/dockerfile:1
+
+# uv-managed Python image keeps the toolchain reproducible. Pinned to 3.13 for
+# broad wheel availability (asyncpg etc.); bump when 3.14 wheels are ubiquitous.
+FROM ghcr.io/astral-sh/uv:python3.13-bookworm-slim
+
+ENV PYTHONUNBUFFERED=1 \
+    PYTHONDONTWRITEBYTECODE=1 \
+    UV_COMPILE_BYTECODE=1 \
+    UV_LINK_MODE=copy
+
+WORKDIR /app
+
+# Dependencies first for layer caching. uv.lock is optional on first build;
+# `uv sync` resolves and writes it if absent.
+COPY pyproject.toml uv.lock* ./
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv sync --no-dev
+
+# Application source (project is package=false, so no install step needed).
+COPY app ./app
+
+EXPOSE 8000
+
+CMD ["uv", "run", "--no-dev", "uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]