feat: Dedicated Approval Queue for Message Drafts

[gromdimon]

Summary

Instead of scattered approval prompts, implement a dedicated queue for pending approvals.

Proposed UI

• New "Approvals" tab or section on home page
• Shows all pending message drafts waiting for approval
• Batch approve/reject capability
• Edit before sending

Example

┌─────────────────────────────────────────┐
│  Pending Approvals                  (3) │
├─────────────────────────────────────────┤
│  📤 Message to Sarah (Telegram)         │
│  "Hi Sarah, confirming 2pm tomorrow..." │
│  [Approve] [Edit] [Reject]              │
├─────────────────────────────────────────┤
│  📤 Message to Mike (WhatsApp)          │
│  "Following up on the invoice..."       │
│  [Approve] [Edit] [Reject]              │
└─────────────────────────────────────────┘

Acceptance Criteria

• Dedicated approval queue view
• Show message preview with recipient info
• Approve/Edit/Reject actions
• Batch operations
• Integrate with secretary agent workflow