Implementation of Background Services & Notification System

[chebizarro]

This PR delivers a comprehensive set of enhancements and fixes across the codebase, with a primary focus on:

• Robust background service management for message/event handling
• Reliable and user-friendly notification delivery throughout the app
• Improved state synchronization and error handling
• General codebase cleanup, refactoring, and bug fixes

Key Points

Background Services

• Refactored and stabilized the background service architecture for both mobile and desktop.
• Improved session management and background message polling, ensuring that order and chat events are processed even when the app is not in the foreground.
• Added/updated lifecycle hooks to start, stop, and update background services in response to user actions and app state changes.
• Enhanced error logging and recovery for background isolates and service failures.
• Ensured background services respect user settings and update their configuration dynamically.

Notification System

• Centralized notification logic via a dedicated notification provider and notifier classes.
• Improved reliability of in-app notifications for all Mostro protocol events, including PaymentRequest, CantDo, Dispute, and Order updates.
• Added contextual information to notifications (e.g., order IDs, reasons, next actions) for better user guidance.
• Fixed issues where notifications could be missed or repeated due to provider disposal or subscription errors.

Finite State Machine & Event Handling

• Refactored notifiers (including PaymentRequestNotifier) to ensure correct subscription to message streams and robust state transitions.
• Improved synchronization between MostroStorage and notifier families, fixing issues where events were not reflected in the UI.
• Ensured all notifiers are initialized and synchronized at app startup, addressing edge cases with missed or out-of-order events.

Codebase Quality & Reliability

• Cleaned up unused imports, dead code, and redundant logic across providers and notifiers.
• Improved logging and error reporting for storage, background, and notification subsystems.
• Added/updated unit and integration tests for background services, notification flows, and MostroStorage methods.
• Enhanced documentation and inline comments for maintainability.

Other Notable Changes

• Updated provider initialization logic to avoid premature disposal and ensure all relevant state is retained.
• Improved user experience in trade/order screens by making notifications and state transitions more responsive and reliable.
• Refined session and chat management to ensure seamless transitions between foreground and background states.

Migration & Testing Notes
Migration: Major breaking changes to data models, users should not use on live data.
Testing: Please report any missed notifications or unexpected state changes.
This PR lays the groundwork for a more robust, user-friendly, and reliable Mostro Mobile experience, especially in scenarios involving background activity and real-time notifications.

Summary by CodeRabbit

• New Features

  • Added background service support for persistent event subscriptions and notifications on mobile and desktop.
  • Introduced local notification functionality for new Mostro events.
  • Implemented system tray integration for desktop platforms.
  • Added reactive, success-aware action buttons throughout the app.
  • Provided deterministic, memorable nicknames for user public keys.
  • Enhanced About screen with clearer app and instance information.
  • Added lifecycle management for app foreground/background transitions.
  • Introduced Mostro finite-state-machine (FSM) for order lifecycle management.
  • Added new reactive streams for messages and order status.
  • Added notification permission request helper for Android 13+.

• Improvements

  • Unified and streamlined state management using Riverpod providers and Notifiers.
  • Standardized page transitions with fade animations.
  • Improved order and trade detail screens with clear finite-state-machine-driven actions.
  • Enhanced session and order initialization logic for better reliability.
  • Optimized message and event storage with new querying and streaming capabilities.
  • Updated notification and permission handling for Android and iOS.
  • Improved error handling, loading states, and manual refresh controls in trade and chat screens.
  • Refined background service initialization and communication.
  • Improved MostroService and NostrService with provider-driven architecture.
  • Enhanced chat room subscription and message deduplication logic.
  • Improved button state management and error handling in order submission.
  • Refined session notifier with filtering and update methods.

• Bug Fixes

  • Fixed serialization bugs in order models.
  • Corrected import paths and removed unused or redundant code.
  • Fixed null handling in session peer setter.
  • Fixed notification icon metadata and Android manifest permissions.

• Refactor

  • Simplified and modernized repository and storage APIs.
  • Centralized and modularized background service and notification logic.
  • Removed unused classes, screens, and widgets for maintainability.
  • Consolidated imports and updated provider dependencies.
  • Replaced event bus with storage-based reactive streams.
  • Refactored Mostro FSM and order notifiers to remove generics and improve state handling.
  • Updated mocks to align with new interfaces and signatures.

• Documentation

  • Added a comprehensive CONTRIBUTING.md guide.
  • Updated README with new features and progress.

• Chores

  • Updated and added dependencies for background services, notifications, and system tray support.
  • Integrated CocoaPods for iOS and macOS.
  • Adjusted build configurations and plugin registrations across platforms.
  • Added database providers for separate event and main databases.
  • Added notification initialization and permission requests in app startup.

• Tests

  • Updated and expanded mock classes to align with new interfaces and features.