fix: Update path filters, test tags and backend processing (#6613)

* ✨ (tests): update tag value from "@starter-project" to "@starter-projects" for consistency across test files.

* 📝 (changes-filter.yaml): add new path "src/backend/base/langflow/custom/**" to starter-projects section
♻️ (changes-filter.yaml): remove path "src/backend/base/langflow/components/**" from components section and add it to starter-projects section
♻️ (changes-filter.yaml): add new path "src/backend/base/langflow/custom/**" to components section

* 🐛 (component.py): fix a bug where the status was not being returned when there is only one output in the component

* 🔧 (ci.yml): Expand path filter outputs for more comprehensive CI testing

* fix docstring placement

* ✨ (group.spec.ts): update click event modifiers to use "ControlOrMeta" for better cross-platform compatibility

* ✨ (changes-filter.yaml): add new directory "src/backend/base/langflow/graph/" to starter-projects for processing in the build pipeline.

* 🔄 Refactor graph data structures from sets to lists for performance and compatibility

* 🔧 Optimize RunnableVerticesManager predecessor checks and type hints

---------

Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>

src/frontend/tests/core/integrations/Simple Agent.spec.ts

@@ -6,7 +6,7 @@ import { initialGPTsetup } from "../../utils/initialGPTsetup";
 
 test(
   "Simple Agent",
-  { tag: ["@release", "@starter-project"] },
+  { tag: ["@release", "@starter-projects"] },
   async ({ page }) => {
     test.skip(
       !process?.env?.OPENAI_API_KEY,