feat: add limited visitor tokens

tests/unit/api/test_visitor_tokens.py

@@ -0,0 +1,14 @@
+from fastapi.testclient import TestClient
+
+from app.main import create_app
+
+
+def test_visitor_token_endpoint_returns_short_lived_bearer_token() -> None:
+    with TestClient(create_app()) as client:
+        response = client.post("/api/v1/visitor-tokens")
+
+    assert response.status_code == 201
+    body = response.json()
+    assert isinstance(body["access_token"], str)
+    assert body["token_type"] == "Bearer"
+    assert body["expires_in"] == 900