API: blueprint flask-smorest + endpoint /health (#78)

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

tests/api/test_health.py

@@ -0,0 +1,16 @@
+from flask import Flask
+
+from src.api import init_api
+
+
+def _make_app():
+    app = Flask(__name__)
+    init_api(app)
+    return app
+
+
+def test_health_returns_ok_without_auth():
+    app = _make_app()
+    resp = app.test_client().get("/api/v1/health")
+    assert resp.status_code == 200
+    assert resp.get_json() == {"status": "ok"}