Scan a specific TXID for incoming silent payment

[chaitika]

Motivation : Allow users to check if a specific transaction contains a silent payment to their wallet, without waiting for a full block scan.

Depends on : add endpoint to get txn by txid

Estimated Milestones :

• wallet method, indexer client and UI to scan by txid for SP: FEAT: Track payment by TXID #73
• feature to scan by txid for normal (non SP) payment
• Tests
• Floating lens button on non-home screens
• Dark mode support for the feature