[FE] Shop, Inventory, and Equip Flow

[MelonChicken]

Goal

Build shop, inventory, and item equip/unequip flow.

Tasks

• Build shop page
• Display shop items
• Connect shop item API
• Connect purchase API
• Build inventory page
• Display owned items
• Connect inventory API
• Add equip/unequip interaction
• Update dashboard after item equip

Done When

• User can view shop items
• User can buy items with will
• User can view owned items
• User can equip/unequip items
• Equipped items are reflected on the egg dashboard

[Driedoutjerky]

Closed by #30