DO NOT MERGE, Refactor: ApiHandler Migration to Service Layer Architecture

[cakesoft-shashank]

This PR migrates the monolithic ApiHandler class to a modular service layer architecture with dedicated services and React hooks. This refactoring improves code maintainability, testability, and follows React best practices by separating concerns.

The legacy ApiHandler class had grown to over 3,400 lines and violated several software engineering principles:

Architecture Changes

New Service Layer

Created six specialized services following the Single Responsibility Principle:

1. AuthService (src/services/auth/AuthService.ts)

• User authentication and authorization
• PIN/biometric verification
• Session management
• Replaced ApiHandler initialization with NodeService.initApi()

2. AppService (src/services/app/AppService.ts)

• App setup and initialization
• Release notes and version history
• FCM topic management
• Migrated from ApiHandler to use WalletService, NodeService, BackupService, and RgbService

3. WalletService (src/services/wallet/WalletService.ts)

• Wallet creation and management
• Transaction operations
• Balance tracking
• Profile updates
• New implementations: receiveTestSats, updateProfile, removeWalletPicture
• Migrated: getNodeOnchainBtcTransactions to use NodeService

4. RgbService (src/services/rgb/RgbService.ts)

• RGB asset operations (NIA, CFA, UDA)
• Asset issuance and transfers
• Invoice generation
• Channel management
• New implementations: receiveAsset, searchAssetFromRegistry, handleTransferFailure

5. NodeService (src/services/node/NodeService.ts)

• RGB node connection and management
• Node API initialization
• Node information retrieval
• New implementation: getNodeOnchainBtcTransactions

6. BackupService (src/services/backup/BackupService.ts)

• App backup and restore
• Cloud backup management
• File download operations

Custom React Hooks

Created six custom hooks for React components:

• useAuth - Authentication operations
• useApp - App-level operations
• useWallet - Wallet operations
• useRgb - RGB asset operations
• useNode - Node management
• useBackup - Backup operations