fix(api): stabilize palette and preset endpoints

Made-with: Cursor

src/controllers/palette.py

@@ -17,9 +17,9 @@ async def list_palettes(request):
 @controller.get('/<id>')
 async def get_palette(request, id):
     """Get a specific palette by ID."""
-    palette = palettes.read(id)
-    if palette:
-        return json.dumps({"colors": palette, "id": str(id)}), 200, {'Content-Type': 'application/json'}
+    if str(id) in palettes:
+        palette = palettes.read(id)
+        return json.dumps({"colors": palette or [], "id": str(id)}), 200, {'Content-Type': 'application/json'}
     return json.dumps({"error": "Palette not found"}), 404
 
 @controller.post('')
@@ -30,11 +30,8 @@ async def create_palette(request):
         colors = data.get("colors", None)
         # Palette no longer needs a name; only colors are stored.
         palette_id = palettes.create("", colors)
-        palette = palettes.read(palette_id) or {}
-        # Include the ID in the response payload so clients can link it.
-        palette_with_id = {"id": str(palette_id)}
-        palette_with_id.update(palette)
-        return json.dumps(palette_with_id), 201, {'Content-Type': 'application/json'}
+        created_colors = palettes.read(palette_id) or []
+        return json.dumps({"id": str(palette_id), "colors": created_colors}), 201, {'Content-Type': 'application/json'}
     except Exception as e:
         return json.dumps({"error": str(e)}), 400
 
@@ -47,10 +44,8 @@ async def update_palette(request, id):
         if "name" in data:
             data.pop("name", None)
         if palettes.update(id, data):
-            palette = palettes.read(id) or {}
-            palette_with_id = {"id": str(id)}
-            palette_with_id.update(palette)
-            return json.dumps(palette_with_id), 200, {'Content-Type': 'application/json'}
+            colors = palettes.read(id) or []
+            return json.dumps({"id": str(id), "colors": colors}), 200, {'Content-Type': 'application/json'}
         return json.dumps({"error": "Palette not found"}), 404
     except Exception as e:
         return json.dumps({"error": str(e)}), 400