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

tests/services/test_download_manager_basic.py

@@ -123,10 +123,7 @@ def metadata_provider(monkeypatch):
     class DummyProvider:
         def __init__(self):
             self.calls = []
-
-        async def get_model_version(self, model_id, model_version_id):
-            self.calls.append((model_id, model_version_id))
-            return {
+            self.payload = {
                 "id": 42,
                 "model": {"type": "LoRA", "tags": ["fantasy"]},
                 "baseModel": "BaseModel",
@@ -141,6 +138,10 @@ def metadata_provider(monkeypatch):
                 ],
             }
 
+        async def get_model_version(self, model_id, model_version_id):
+            self.calls.append((model_id, model_version_id))
+            return self.payload
+
     provider = DummyProvider()
     monkeypatch.setattr(
         download_manager,
@@ -233,6 +234,165 @@ async def test_successful_download_uses_defaults(
     assert captured["download_urls"] == ["https://example.invalid/file.safetensors"]
 
 
+@pytest.mark.asyncio
+async def test_download_accepts_enhancement_lora_primary_file(
+    monkeypatch, scanners, metadata_provider, tmp_path
+):
+    """A version whose only file has type 'Enhancement LoRA' (Anima/AIR
+    image-editing LoRAs) must download — previously failed with
+    "No suitable file found in metadata" because the type was missing from
+    the primary-file weights allowlist."""
+    manager = DownloadManager()
+    metadata_provider.payload = {
+        "id": 3219121,
+        "model": {"type": "LORA", "tags": ["style"]},
+        "baseModel": "Anima",
+        "creator": {"username": "Deskup"},
+        "files": [
+            {
+                "id": 3100968,
+                "type": "Enhancement LoRA",
+                "primary": True,
+                "name": "deskup-anima-edit-general.safetensors",
+                "sizeKB": 358501.13,
+                "downloadUrl": "https://example.invalid/deskup-anima-edit-general.safetensors",
+            }
+        ],
+    }
+
+    captured = {}
+
+    async def fake_execute_download(self, **kwargs):
+        captured.update(
+            {
+                "download_urls": kwargs["download_urls"],
+                "model_type": kwargs["model_type"],
+            }
+        )
+        return {"success": True}
+
+    monkeypatch.setattr(
+        DownloadManager, "_execute_download", fake_execute_download, raising=False
+    )
+
+    result = await manager.download_from_civitai(
+        model_id=2850692,
+        model_version_id=3219121,
+        save_dir=str(tmp_path),
+        use_default_paths=True,
+        progress_callback=None,
+        source=None,
+    )
+
+    assert result["success"] is True
+    assert captured["model_type"] == "lora"
+    assert captured["download_urls"] == [
+        "https://example.invalid/deskup-anima-edit-general.safetensors"
+    ]
+
+
+@pytest.mark.asyncio
+async def test_download_falls_back_to_civitai_primary_flag_regardless_of_type(
+    monkeypatch, scanners, metadata_provider, tmp_path
+):
+    """If no weights-type file exists, trust CivitAI's `primary` flag on any
+    file — mirrors CivitAI's getPrimaryFile() which never excludes a file by
+    type."""
+    manager = DownloadManager()
+    metadata_provider.payload = {
+        "id": 77,
+        "model": {"type": "LORA", "tags": ["concept"]},
+        "baseModel": "Anima",
+        "creator": {"username": "Author"},
+        "files": [
+            {
+                "id": 100,
+                "type": "Other",
+                "primary": True,
+                "name": "custom-type-lora.safetensors",
+                "downloadUrl": "https://example.invalid/custom-type-lora.safetensors",
+            }
+        ],
+    }
+
+    captured = {}
+
+    async def fake_execute_download(self, **kwargs):
+        captured["download_urls"] = kwargs["download_urls"]
+        return {"success": True}
+
+    monkeypatch.setattr(
+        DownloadManager, "_execute_download", fake_execute_download, raising=False
+    )
+
+    result = await manager.download_from_civitai(
+        model_version_id=77,
+        save_dir=str(tmp_path),
+        use_default_paths=True,
+        progress_callback=None,
+        source=None,
+    )
+
+    assert result["success"] is True
+    assert captured["download_urls"] == [
+        "https://example.invalid/custom-type-lora.safetensors"
+    ]
+
+
+@pytest.mark.asyncio
+async def test_download_prefers_weights_file_over_non_weights_primary(
+    monkeypatch, scanners, metadata_provider, tmp_path
+):
+    """A Config/Archive-type primary must never replace an existing weights
+    file — the weights file wins even without the primary flag."""
+    manager = DownloadManager()
+    metadata_provider.payload = {
+        "id": 78,
+        "model": {"type": "LORA", "tags": ["concept"]},
+        "baseModel": "BaseModel",
+        "creator": {"username": "Author"},
+        "files": [
+            {
+                "id": 201,
+                "type": "Config",
+                "primary": True,
+                "name": "config.json",
+                "downloadUrl": "https://example.invalid/config.json",
+            },
+            {
+                "id": 202,
+                "type": "Model",
+                "primary": False,
+                "name": "weights.safetensors",
+                "downloadUrl": "https://example.invalid/weights.safetensors",
+            },
+        ],
+    }
+
+    captured = {}
+
+    async def fake_execute_download(self, **kwargs):
+        captured["download_urls"] = kwargs["download_urls"]
+        return {"success": True}
+
+    monkeypatch.setattr(
+        DownloadManager, "_execute_download", fake_execute_download, raising=False
+    )
+
+    result = await manager.download_from_civitai(
+        model_version_id=78,
+        save_dir=str(tmp_path),
+        use_default_paths=True,
+        progress_callback=None,
+        source=None,
+    )
+
+    assert result["success"] is True
+    assert captured["download_urls"] == [
+        "https://example.invalid/weights.safetensors"
+    ]
+
+
 @pytest.mark.asyncio
 async def test_download_keeps_save_dir_when_use_save_dir_as_root(
     monkeypatch, scanners, metadata_provider, tmp_path