Pick cheapest GPU SKU and pin the VM to an existing disk AZ.

Scan ru-6 by Nova availability zones (a/b/c). First boot uses FLAVOR_SIZE_PRESET=cheap; reruns stay on the disk segment.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_server_plan.py

@@ -29,9 +29,9 @@ def test_prompt_server_plan_with_ranked(monkeypatch, tmp_path):
 
     monkeypatch.setattr(
         "gpu_rent.ux.list_ranked_flavors",
-        lambda flavors, cfg: [f1, f2],
+        lambda flavors, cfg, **kw: [f1, f2],
     )
-    answers = iter(["2", "200", "2"])
+    answers = iter(["1", "2", "200", "2"])
 
     def ask(msg: str, default: str = "") -> str:
         return next(answers)