Add clear all button for hopper queue

[warmonger0]

Description

Add a "Clear All" button to the hopper queue panel that removes all queued tasks at once. This provides quick cleanup when users want to reset the queue.

Requirements

1. Add a "Clear All" button in the hopper panel header
2. When clicked, remove ALL tasks from the phase_queue
3. Show confirmation dialog before clearing (important for safety)
4. Update UI immediately after clearing
5. Show success notification with count of cleared tasks
6. Proper error handling if deletion fails

Implementation Details

• Frontend: Add button to QueuePanel header/toolbar
• Backend: Create DELETE /api/v1/queue/clear-all endpoint (or batch delete)
• Database: Remove all records from phase_queue table
• WebSocket: Broadcast queue cleared event to all clients

UI/UX

• Button should be prominent but not accidentally clickable
• Use warning color (red/orange) to indicate destructive action
• Confirmation dialog should clearly state: "Clear X queued tasks?"
• Button text: "Clear All" or "Clear Queue" with icon (🗑️ or ❌)
• Disable button when queue is empty
• Show loading state during deletion

Safety Considerations

• MUST show confirmation dialog (non-optional)
• Should log the action for audit purposes
• Cannot undo this action

Priority

Medium - Quality of life improvement for hopper management

adw_sdlc_complete_iso

[warmonger0]

[ADW-AGENTS] 🤖 ADW Webhook: Detected adw_sdlc_complete_iso workflow request

Starting workflow with ID: d9ccd401
Workflow: adw_sdlc_complete_iso 🏗️
Model Set: base ⚙️
Reason: New issue with adw_sdlc_complete_iso workflow

Logs will be available at: agents/d9ccd401/adw_sdlc_complete_iso/