Implement functionality for adding an item to cart

[alexzhang1618]

Info

Closes #148.

Changes

• Refactor cart functions into CartService
• Implement adding an item to cart from the item page

Type of Change

• Bug Fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as
  expected)
• Logistics Change (A change to a README, description, or dev workflow setup like
  linting/formatting)
• Continuous Integration Change (Related to deployment steps or continuous integration
  workflows)
• Other: (Fill In)

Testing

I have tested that my changes fully resolve the linked issue ...

• locally on Desktop.
• on the live deployment preview on Desktop.
• on the live deployment preview on Mobile.
• I have added new Cypress tests that are passing.

Checklist

• I have performed a self-review of my own code.
• I have followed the style guidelines of this project.
• I have documented any new functions in /src/lib/* and commented hard to understand areas
  anywhere else.
• My changes produce no new warnings.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
membership-portal-ui-v2	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Mar 12, 2024 1:54am

[SheepTester]

i dont understand why "Some items in your cart are not available"

[SheepTester]

lgtm