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/integration/test_deck_vector_search.py

@@ -207,10 +207,13 @@ async def test_deck_card_chunk_context(nc_client):
 
         # Fetch chunk context (simulates viz UI request)
         # The chunk spans the title, so start=0 and end=len(card_title)
+        # doc_id is str — keyword-indexed in Qdrant payload; the real
+        # callers (viz_routes.py from URL path; server/semantic.py from
+        # str(result.id)) all stringify before reaching this entry point.
         context = await get_chunk_with_context(
             nc_client=nc_client,
             user_id=nc_client.username,
-            doc_id=card.id,
+            doc_id=str(card.id),
             doc_type="deck_card",
             chunk_start=0,
             chunk_end=len(card_title),