feat(base-models): add Ernie, Ernie Turbo, Nucleus base model types (#922)

- Ernie & Anima: auto-fetched via CivitaiBaseModelService from Civitai API
- Ernie Turbo & Nucleus: pre-added as hardcoded constants (not yet in Civitai API)
- Added abbreviations (ERNI, ETRB, NUCL) and category entries across all layers

py/utils/constants.py

@@ -178,5 +178,8 @@ SUPPORTED_DOWNLOAD_SKIP_BASE_MODELS = frozenset(
         "Wan Video 2.5 I2V",
         "Hunyuan Video",
         "Anima",
+        "Ernie",
+        "Ernie Turbo",
+        "Nucleus",
     ]
 )