fix(updates): mark cross-folder versions as in-library during folder-filtered refresh (#997)

When refreshing updates with a folder filter, versions already present in
other folders were excluded from the is_in_library check, making them
appear as available updates. When the user tried to download, the global
check found the file already exists and returned 'model already exists'.

Fix by also collecting the cross-folder version set when folder_path is
provided, and using the union (folder-filtered + cross-folder) for
is_in_library in both _build_record_from_remote and
_merge_with_local_versions.

tests/services/test_model_update_service.py

@@ -579,3 +579,45 @@ async def test_update_in_library_versions_populates_metadata(tmp_path):
     assert version.preview_url == "https://example.com/preview.png"
     assert version.is_in_library is True
 
+
+@pytest.mark.asyncio
+async def test_refresh_folder_filter_considers_cross_folder_versions(tmp_path):
+    """When refreshing by folder, versions in other folders must still be
+    considered in-library so they aren't reported as available updates."""
+    db_path = tmp_path / "updates.sqlite"
+    service = ModelUpdateService(str(db_path), ttl_seconds=0)
+    # Same model (modelId=1) in two folders with different versions
+    raw_data = [
+        {"civitai": {"modelId": 1, "id": 11}, "folder": "folder_a"},
+        {"civitai": {"modelId": 1, "id": 15}, "folder": "folder_b"},
+    ]
+    scanner = DummyScanner(raw_data)
+    # Remote offers: 11 (in folder_a), 15 (in folder_b), 20 (truly new)
+    provider = DummyProvider(
+        {
+            "modelVersions": [
+                {"id": 11, "files": [], "images": []},
+                {"id": 15, "files": [], "images": []},
+                {"id": 20, "files": [], "images": []},
+            ]
+        }
+    )
+
+    await service.refresh_for_model_type(
+        "lora", scanner, provider, folder_path="folder_a",
+    )
+    record = await service.get_record("lora", 1)
+
+    assert record is not None
+
+    # Version 15 is in folder_b — must be in_library even when filtering by folder_a
+    v15 = next(v for v in record.versions if v.version_id == 15)
+    assert v15.is_in_library is True
+
+    # Version 20 is truly new — should not be in_library
+    v20 = next(v for v in record.versions if v.version_id == 20)
+    assert v20.is_in_library is False
+
+    # has_update must be True (version 20 > max_in_library=15)
+    assert record.has_update() is True
+