added reasoning to labeling queues

[skull8888888]

[!IMPORTANT] Adds optional reasoning to labels in queues, updates CSS background color, and modifies queue component for reasoning input.

• Behavior:
  • Adds optional reasoning field to labels in removeQueueItemSchema in route.ts.
  • Updates addedLabels state in queue.tsx to include reasoning.
  • Allows users to input reasoning for labels using DefaultTextarea in queue.tsx.
• CSS:
  • Changes --background color in globals.css from 0 0% 8% to 0 0% 4%.

^{This description was created by for 415ac37540a45fc819ff2c348a3e6ef7b66ffd27. It will automatically update as commits are pushed.}