chore(devops): project skeleton — uv, docker compose, Makefile, CI

One Postgres with isolated identity/clinical databases and roles (ADR-003),
FastAPI /health, Streamlit placeholder, typed settings with offline defaults.

Refs #1

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_smoke.py

@@ -0,0 +1,15 @@
+from fastapi.testclient import TestClient
+
+from app.config import Settings
+from app.main import app
+
+
+def test_health() -> None:
+    with TestClient(app) as client:
+        assert client.get("/health").json() == {"status": "ok"}
+
+
+def test_offline_defaults() -> None:
+    settings = Settings(_env_file=None)
+    assert settings.llm_provider == "mock"
+    assert settings.demo_clock is True