feat(platform): Onboarding flow backend

[kcze]

This PR adds backend to make Onboarding UI added in #9485 functional and adds missing confetti screen at the end of Onboarding.

Visit /onboarding/reset to reset onboarding state, otherwise it'll always redirect to /library once finished.

Changes 🏗️

• Onboarding opens automatically on sign up and login (if unfinished) for all users
• Update db schema to add UserOnboarding and add migration
• Add GET and PATCH /onboarding endpoints and logic to retrieve and update data Onboarding for a user
• Update POST /library/agents endpoint (addMarketplaceAgentToLibrary), so it includes input and output nodes; these are needed to know input schema for the Onboarding
• Use new endpoints during onboarding to fetch and update data
• Use agents from the marketplace and their input schema for the onboarding
• Redirect outside onboarding if finished and resume on proper page
• Add canvas-confetti and @types/canvas-confetti frontend packages
• Add and show congrats confetti screen when user runs and agent and before opening library
• Minor design updates and onboarding fixes

Checklist 📋

For code changes:

• I have clearly listed my changes in the PR description
• I have made a test plan
• I have tested my changes according to the test plan:
  • ...

[netlify]

✅ Deploy Preview for auto-gpt-docs-dev canceled.

Name	Link
🔨 Latest commit	5e1b513
🔍 Latest deploy log	https://app.netlify.com/sites/auto-gpt-docs-dev/deploys/67c5e25f897dcd0008562fd7

[deepsource-io]

Here's the code health analysis summary for commits ef00ab5..5e1b513. View details on DeepSource ↗.

Analysis Summary

Analyzer	Status	Summary	Link
JavaScript	✅ Success	❗ 97 occurences introduced 🎯 56 occurences resolved	View Check ↗
Python	✅ Success	❗ 42 occurences introduced 🎯 29 occurences resolved	View Check ↗

---

💡 If you’re a repository administrator, you can configure the quality gates from the settings.

[netlify]

✅ Deploy Preview for auto-gpt-docs canceled.

Name	Link
🔨 Latest commit	5e1b513
🔍 Latest deploy log	https://app.netlify.com/sites/auto-gpt-docs/deploys/67c5e25f897dcd0008562fd3

[github-actions]

This pull request has conflicts with the base branch, please resolve those so we can evaluate the pull request.

[github-actions]

Conflicts have been resolved! 🎉 A maintainer will review the pull request shortly.