Description/Comment:

Set up onboarding docs in Storybook by creating MDX files for the following sections:

• Welcome
• Onboarding
• Tech Stack
• CloneWithGit
• CloneWithGitKraken
• Backend
• ProjectStructure

Update the .storybook/main.ts configuration to consolidate and simplify the stories array so all onboarding docs are automatically included in the Storybook sidebar.