refactor(models): unify preset names

tests/config/test_model_presets.py

@@ -275,6 +275,30 @@ def test_model_presets_accepts_camel_case_root_key() -> None:
     assert config.model_presets["fast"].provider == "openai"
 
 
+def test_legacy_model_preset_label_is_ignored() -> None:
+    config = Config.model_validate({
+        "modelPresets": {
+            "gpt-5-6-sol": {
+                "label": "Codex",
+                "model": "openai-codex/gpt-5.6-luna",
+            }
+        }
+    })
+
+    assert set(config.model_presets) == {"gpt-5-6-sol"}
+    assert "label" not in config.model_presets["gpt-5-6-sol"].model_dump()
+
+
+def test_model_preset_names_are_unique_ignoring_case() -> None:
+    with pytest.raises(ValueError, match="unique ignoring case"):
+        Config.model_validate({
+            "modelPresets": {
+                "Fast": {"model": "openai/gpt-4.1-mini"},
+                "fast": {"model": "openai/gpt-4.1"},
+            }
+        })
+
+
 def test_model_presets_serializes_with_camel_case_root_key() -> None:
     config = Config.model_validate({
         "model_presets": {