fix: use correct filetype for Workshop collections

Was using filetype=2 (Artwork) instead of filetype=1 (Collections).
Per Steamworks API docs, EPublishedFileInfoMatchingFileType values:
- 0 = Items (regular mods)
- 1 = Collections
- 2 = Art
- 3 = Videos

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: CodeKeanu

src/steam_mcp/endpoints/steam_workshop.py

@@ -463,7 +463,7 @@ async def search_workshop_collections(
         params: dict[str, Any] = {
             "appid": app_id,
             "query_type": query_type,
-            "filetype": 2,  # Collections only
+            "filetype": 1,  # Collections (1=Collections, 2=Art, 0=Items)
             "numperpage": min(max_results, 50),
             "return_metadata": True,
             "return_tags": True,

tests/test_steam_workshop.py

@@ -242,7 +242,7 @@ async def test_search_collections_with_query(self, workshop_service, mock_client
 
         call_args = mock_client.get.call_args
         assert call_args[1]["params"]["search_text"] == "weapon skins"
-        assert call_args[1]["params"]["filetype"] == 2  # Collections only
+        assert call_args[1]["params"]["filetype"] == 1  # Collections only
 
     @pytest.mark.asyncio
     async def test_search_collections_with_tags(self, workshop_service, mock_client):
@@ -258,7 +258,7 @@ async def test_search_collections_with_tags(self, workshop_service, mock_client)
         call_args = mock_client.get.call_args
         assert call_args[1]["params"]["requiredtags[0]"] == "Maps"
         assert call_args[1]["params"]["requiredtags[1]"] == "Competitive"
-        assert call_args[1]["params"]["filetype"] == 2
+        assert call_args[1]["params"]["filetype"] == 1  # Collections only
 
     @pytest.mark.asyncio
     async def test_search_collections_empty_results(self, workshop_service, mock_client):