[Feature] Send push notification upon flash support receive top-up via bank transfer request

[islandbitcoin]

Send a push notification to the user's mobile device when they initiate a top-up via bank transfer. This notification should include the bank transfer instructions and serve as a reference for the user while they complete the transfer.

Current Behavior

• User selects bank transfer option in mobile app
• Bank transfer details are displayed on screen
• No push notification is sent
• User must keep app open or take screenshots to remember transfer details

Expected Behavior

• When user confirms bank transfer top-up, immediately send push notification
• Notification should include:
  • Amount to transfer
  • Bank account details (account number, routing, reference)
  • Unique reference/memo code for identification
  • Expiration time (if applicable)
• Notification should be persistent/non-dismissible if possible
• Optional: Send reminder notification if transfer not received within X hours

Implementation Details

Relevant Files:

• /flash-mobile/app/screens/buy-bitcoin-flow/BankTransfer.tsx - Where bank transfer is initiated
• /flash-mobile/app/screens/buy-bitcoin-flow/BuyBitcoinDetails.tsx - Where user selects bank transfer option
• /src/graphql/public/root/mutation/ - May need new mutation for bank transfer initiation
• /src/services/notifications/ - Notification service

Suggested Implementation:

1. Create GraphQL mutation for bank transfer top-up initiation (if not exists)
2. Add notification trigger in the mutation resolver
3. Include all necessary bank transfer details in notification payload
4. Format notification for clear display on mobile devices

Example notification content:
💰 Bank Transfer Top-up Initiated

Amount: $50.00
Account: 12345678
Routing: 987654321
Reference: FLASH-USER123-20240115

Please include the reference in your transfer memo.
This request expires in 24 hours.

Acceptance Criteria

• Notification sent immediately upon bank transfer selection
• All transfer details included in notification
• Reference code is unique and traceable
• Notification persists in notification center
• Clear instructions included in notification
• Handles different currencies (USD/JMD)
• Optional: Follow-up reminder if no transfer received

Additional Context

• Reduces support tickets from users who forgot transfer details
• Improves completion rate for bank transfers
• This should be in addition to Email and SMS/WhatsApp notifications for critical information
• May need to store transfer initiation in database for tracking

[brh28]