test: align CI assertions with documented contracts

Two unrelated CI failures on this branch, one fix each:

- tests/integration/test_deck_vector_search.py: pass str(card.id) to
  get_chunk_with_context. The function's contract is doc_id: str
  (keyword-indexed in Qdrant), and real callers (viz_routes.py URL
  path, server/semantic.py via str(result.id)) all stringify. The
  test was the only int caller, hitting the .isdigit() guard added
  earlier on this branch.

- tests/server/login_flow/test_login_flow_integration.py:
  test_check_status_provisioned now accepts scopes=None as valid.
  Per ProvisionStatusResponse in models/auth.py, None is the
  documented sentinel for "all scopes granted" — and the web
  provisioning path (provision_routes.py, used by Astrolabe's
  "Enable Semantic Search" flow exercised by the new regression test
  added on this branch) stores exactly that. The previous
  is-not-None assertion hid behind test order until that flow ran.

- Replace anyio.sleep(0) with anyio.lowlevel.checkpoint()

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/server/login_flow/test_login_flow_integration.py

@@ -43,7 +43,13 @@ class TestLoginFlowAuthTools:
         data = json.loads(result.content[0].text)
         assert data["status"] == "provisioned"
         assert data["username"] is not None
-        assert data["scopes"] is not None
+        # ``scopes`` may legitimately be ``None`` — per ProvisionStatusResponse
+        # in models/auth.py, ``None`` is the documented sentinel for "all
+        # scopes granted" and is what the web provisioning path
+        # (``provision_routes.py``, used by Astrolabe's "Enable Semantic
+        # Search" flow) stores. So accept either a non-empty list or None;
+        # the field's *presence* in the payload is what we care about here.
+        assert data["scopes"] is None or len(data["scopes"]) > 0
         logger.info(f"Provisioned as: {data['username']}, scopes: {data['scopes']}")
 
     async def test_provision_access_already_provisioned(