WP-0001-T001: service scaffold (Python, FastAPI, uv, ruff, mypy, pytest)

Lands the smallest credible foundation per ADR-0005:

- pyproject.toml: hatchling build, runtime deps (FastAPI, uvicorn, SQLAlchemy 2.0,
  asyncpg, aiosqlite, alembic, blake3, cbor2, typer, structlog, pydantic,
  pydantic-settings); dev deps (pytest, pytest-asyncio, httpx, hypothesis, ruff,
  mypy); ruff + mypy --strict + pytest configured.
- uv.lock committed.
- Makefile thin shims: install / dev / test / lint / format / type / migrate / clean.
- src/artifactstore/ package skeleton with placeholder __init__.py per concern:
  identity, manifest, events, retention, audit, storage, dataplane, registry,
  api/http (minimal FastAPI app, GET / scaffold banner), cli (typer app with
  version subcommand), config (pydantic-settings).
- tests/{unit,integration}/conftest.py present; unit smoke tests assert package
  imports, HTTP root route, CLI version round-trip, settings defaults.
- .env.example documents ARTIFACTSTORE_DATABASE_URL,
  ARTIFACTSTORE_STORAGE_LOCAL_ROOT, ARTIFACTSTORE_LOG_LEVEL.
- README updated with install / dev / test instructions.
- .gitignore: claude local state, local runtime data (var/, sqlite db).

make lint && make type && make test pass on a clean checkout (4 tests, 20
source files type-clean under mypy --strict).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/artifactstore/api/http/__init__.py

@@ -0,0 +1,24 @@
+"""FastAPI application entry point.
+
+The full registry-aware ``/health`` endpoint lands in
+ARTIFACT-STORE-WP-0001-T014. This scaffold exposes a minimal root route so
+``make dev`` has something to serve while the registry layer is being built.
+"""
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from artifactstore import __version__
+
+app = FastAPI(title="artifact-store", version=__version__)
+
+
+@app.get("/")
+def root() -> dict[str, str]:
+    """Return a service banner indicating the scaffold is up."""
+    return {
+        "service": "artifact-store",
+        "version": __version__,
+        "status": "scaffold",
+    }