Build Inventory Management with Native HTML5 DnD

[frogr]

Acceptance Criteria

• Grid-based inventory display
• Drag items between slots
• Category filtering (Weapons, Apparel, Aid, Misc, Ammo, Mods)
• Quick slots 1-8 with keyboard shortcuts
• Item actions on hover (Equip, Use, Drop)
• Weight tracking and capacity limits

Technical Requirements

• Create inventory_controller.js with drag event handlers
• Use data attributes for item metadata
• AJAX calls for equip/use/drop actions
• Visual feedback during drag (opacity, cursor changes)

API Endpoints

POST /game/items/:id/equip
POST /game/items/:id/use
DELETE /game/items/:id/drop
POST /game/quick_slots (item_id, slot_number)