📋 Add more functionality to Meal Tracker

[EightBitByte]

Summary

There are a few TODOs scattered around the new Meal Tracker feature. Here they are in list form for implementation:

TODOs

• Show when the user has added a meal to their log by adding a toast/sonner (food-card.tsx:42,90)
• Give the user a proper error when they've not signed in before attempting to add a meal (food-card.tsx:55)
• When a user has added a meal to their log, they should be able to adjust the quantity and/or remove the item from their log by clicking the button on the card (food-card.tsx:64)

Bugs

• When clicking to add an item that's already been added, we are met with an error