Fix pyrefly 1.2.0 type-check failure (#1811)

The backend Actions job failed after upgrading Pyrefly to 1.2.0, which
rejected `NewType` identifiers as keys in the foreign-key validation
lookup.

- **Typing:** Update the lookup annotation to accept runtime `NewType`
keys without changing behavior.

```python
check_lookup: dict[Any, CheckCallableT] = {
    StageId: check_stage_belongs_to_tournament,
    TeamId: check_team_belongs_to_tournament,
}
```

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: evroon <11857441+evroon@users.noreply.github.com>

Author: Copilot

backend/bracket/sql/validation.py

@@ -115,7 +115,7 @@ async def check_foreign_keys_belong_to_tournament(
     """
     stages = await get_full_tournament_details(tournament_id)
 
-    check_lookup: dict[type[Any], CheckCallableT] = {  # pyrefly: ignore [bad-assignment]
+    check_lookup: dict[Any, CheckCallableT] = {
         StageId: check_stage_belongs_to_tournament,
         TeamId: check_team_belongs_to_tournament,
         StageItemId: check_stage_item_belongs_to_tournament,