Frontend - Connect wallet + claim destination flow

[MantisClone]

Problem

Payees need a frontend interface to connect their wallet and claim their destination preferences.

Proposed Solution

Create a "Claim Destination" flow in the frontend:

User Flow:

1. Payee connects wallet
2. Payee selects chain and currency for receiving payments
3. System generates destination ID from connected wallet + selections
4. Payee signs EIP-712 message to claim destination
5. System calls POST /v2/destinations/claim
6. Display success with shareable destination ID

UI Concept:

┌─────────────────────────────────────────────┐
│  Claim Your Payment Destination             │
├─────────────────────────────────────────────┤
│  Connected: 0x742d35...35Cc                 │
│                                             │
│  Chain:    [Polygon     ▼]                  │
│  Currency: [USDC        ▼]                  │
│                                             │
│  Your Destination ID:                       │
│  ┌───────────────────────────────────────┐  │
│  │ polygon:0x742d35...35Cc:USDC    [📋]  │  │
│  └───────────────────────────────────────┘  │
│                                             │
│  [ Sign & Claim Destination ]               │
└─────────────────────────────────────────────┘

Frontend Placement

Decision (Feb 2, 2026): Build as a standalone page within the Easy Invoice repository.

• Not integrated with Easy Invoice navigation
• Simple, focused interface for wallet connection and payment preferences
• Wallet connection state will be shared with Easy Invoice if both are open (acceptable tradeoff)

Considerations

• Only show chains/currencies that are supported
• Validate destination ID format before signing
• Handle wallet connection errors gracefully
• Consider showing claim status for existing destinations

Dependencies

• #439 (POST /v2/destinations/claim endpoint)
• #440 (GET /v2/destinations/{id} endpoint)

Parent Issue

Sub-task of api#434 (Destination Preference Epic)