Frontend: Basic control interface for robotic hand

[GoodKimchi]

Create the initial web UI for controlling the robotic hand.

Features:

• Button controls for basic gestures (open, close, wave)
• Connection status indicator
• Layout for video feed display
• Command sending to backend API

[GoodKimchi]

Plan is to build a basic frontend control panel that communicates with the backend API endpoints added in the previous PR.

Initial UI goals:

• Connect button
• Send command button (PINCH 50)
• Disconnect button
• Basic connection/response status display

This will establish the first end-to-end browser → backend → Bluetooth service command flow.

[GoodKimchi]

Implemented the initial frontend control interface for the Yeah Hand system.

Current frontend features:

• Connect button
• Disconnect button
• Dynamic command input field
• Send Command button
• Status display for backend responses/errors

The frontend is now connected to the backend API endpoints and successfully tested through the full simulated flow:

1. Connect to simulated Bluetooth device
2. Send valid commands (e.g. PINCH 50, POWER 100)
3. Reject invalid commands through backend validation
4. Disconnect successfully

Branch:
oscar/frontend-controls

Next step is improving the UI layout and expanding available gesture controls.

[GoodKimchi]

Added additional frontend UX improvements to the control interface.

Updates include:

• Preset gesture buttons (PINCH, POWER, MONKEY, RELAX)

• Improved status feedback messaging

• Status color states for:

  • connection state
  • command activity
  • validation/errors

• Improved dark/light mode readability

• Cleaner frontend layout and spacing

The interface now provides clearer operator feedback during command transitions and error states while keeping manual command entry available for testing/debugging.