fix(download): accept newer CivitAI file types for primary file selection

Downloads failed with "No suitable file found in metadata" for models whose
only file uses newer CivitAI file types (e.g. 'Enhancement LoRA' for
Anima/AIR image-editing LoRAs) because the primary-file allowlist only
covered legacy types.

- unify the weights-type allowlist as MODEL_WEIGHT_FILE_TYPES
  (py/utils/constants.py) and apply it across download, recipe and
  metadata-refresh lookups
- mirror CivitAI's getPrimaryFile() semantics: prefer weights-type primary,
  fall back to weights files, then trust CivitAI's primary flag (excluding
  non-downloadable artifacts like Config/Archive/Workflow)
- mirror the allowlist in the frontend via shared isModelWeightFile() helper
- add regression tests for the Enhancement LoRA primary-file download,
  primary-flag fallback and weights-over-non-weights-primary preference

py/recipes/base.py

@@ -11,7 +11,7 @@ import re
 from typing import Dict, List, Any, Optional, Tuple
 from abc import ABC, abstractmethod
 from ..config import config
-from ..utils.constants import VALID_LORA_TYPES, VALID_CHECKPOINT_SUB_TYPES
+from ..utils.constants import MODEL_WEIGHT_FILE_TYPES, VALID_LORA_TYPES, VALID_CHECKPOINT_SUB_TYPES
 from ..utils.civitai_utils import rewrite_preview_url
 
 logger = logging.getLogger(__name__)
@@ -155,9 +155,9 @@ class RecipeMetadataParser(ABC):
             
             # Process file information if available
             if 'files' in civitai_info:
-                # Find the primary model file (type="Model" and primary=true) in the files list
+                # Find the primary model file (weights-type and primary=true) in the files list
                 model_file = next((file for file in civitai_info.get('files', []) 
-                                    if file.get('type') == 'Model' and file.get('primary') == True), None)
+                                    if file.get('type') in MODEL_WEIGHT_FILE_TYPES and file.get('primary') == True), None)
                 
                 if model_file:
                     # Get size
@@ -261,11 +261,21 @@ class RecipeMetadataParser(ABC):
             checkpoint['id'] = civitai_data.get('id', 0)
 
             if 'files' in civitai_data:
+                # Prefer the file CivitAI marked primary; fall back to any
+                # weights-type file (providers without primary flags).
                 model_file = next(
                     (
                         file
                         for file in civitai_data.get('files', [])
-                        if file.get('type') == 'Model'
+                        if file.get('type') in MODEL_WEIGHT_FILE_TYPES
+                        and file.get('primary') is True
+                    ),
+                    None,
+                ) or next(
+                    (
+                        file
+                        for file in civitai_data.get('files', [])
+                        if file.get('type') in MODEL_WEIGHT_FILE_TYPES
                     ),
                     None,
                 )