Refactor: Secure Keystore, Improve Error Handling, Stabilize Migrations, and Update Documentation

.gitignore

@@ -45,4 +45,14 @@ app.*.map.json
 
 # Project specific
 **/generated/
-android/app/.cxx/
+android/app/.cxx/
+
+# Security - Keystore and sensitive files
+*.jks
+*.keystore
+*.p12
+*.pem
+*.key
+firebase_options.dart
+google-services.json
+GoogleService-Info.plist

CHANGELOG.md

@@ -0,0 +1,211 @@
+# Changelog
+
+All notable changes to IntelliCash will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Planned
+- Enhanced AI-powered transaction categorization
+- New export formats (PDF, Excel)
+- Improved performance and UI responsiveness
+- Additional chart types for analytics
+
+## [7.5.1] - 2024-12-XX
+
+### Security
+- 🔒 **FIXED**: Removed hardcoded Firebase API key from source code
+- 🔒 **FIXED**: Secured keystore files and sensitive configuration
+- 🔒 **ADDED**: Comprehensive security policy and best practices
+- 🔒 **ADDED**: Environment variable-based configuration
+
+### Error Handling
+- 🛠️ **ADDED**: Centralized error handling system
+- 🛠️ **ADDED**: Comprehensive error categorization and logging
+- 🛠️ **ADDED**: User-friendly error messages
+- 🛠️ **ADDED**: Database operation error recovery
+- 🛠️ **ADDED**: Input validation improvements
+- 🛠️ **ADDED**: Network operation error handling
+
+### Documentation
+- 📚 **ADDED**: Comprehensive versioning guide (VERSIONING.md)
+- 📚 **ADDED**: Security policy documentation (SECURITY.md)
+- 📚 **ADDED**: Detailed changelog with semantic versioning
+- 📚 **IMPROVED**: README with security setup instructions
+
+### Technical Improvements
+- 🔧 **IMPROVED**: Database backup and restore functionality
+- 🔧 **IMPROVED**: Key-value service with better error handling
+- 🔧 **IMPROVED**: Text field validation with comprehensive checks
+- 🔧 **IMPROVED**: Application startup error handling
+- 🔧 **IMPROVED**: Firebase initialization with error recovery
+
+## [7.5.0] - 2024-11-XX
+
+### Features
+- ✨ **ADDED**: AI-powered transaction categorization
+- ✨ **ADDED**: Enhanced analytics dashboard
+- ✨ **ADDED**: Smart budget recommendations
+- ✨ **ADDED**: Natural language transaction queries
+- ✨ **ADDED**: Predictive spending insights
+
+### UI/UX
+- 🎨 **IMPROVED**: Modernized transaction interface
+- 🎨 **ADDED**: Dark mode enhancements
+- 🎨 **ADDED**: Customizable dashboard widgets
+- 🎨 **IMPROVED**: Responsive design for tablets
+
+### Performance
+- ⚡ **IMPROVED**: Faster app startup time
+- ⚡ **IMPROVED**: Optimized database queries
+- ⚡ **IMPROVED**: Reduced memory usage
+- ⚡ **IMPROVED**: Better offline functionality
+
+## [7.4.0] - 2024-10-XX
+
+### Features
+- ✨ **ADDED**: CSV export functionality
+- ✨ **ADDED**: Multiple export formats
+- ✨ **ADDED**: Enhanced reporting tools
+- ✨ **ADDED**: Custom report builder
+
+### UI/UX
+- 🎨 **IMPROVED**: Export interface design
+- 🎨 **ADDED**: Progress indicators for long operations
+- 🎨 **IMPROVED**: Better error messages
+- 🎨 **ADDED**: Loading states for data operations
+
+### Technical
+- 🔧 **IMPROVED**: Export performance
+- 🔧 **ADDED**: Background export processing
+- 🔧 **IMPROVED**: File handling capabilities
+
+## [7.3.0] - 2024-09-XX
+
+### Features
+- ✨ **ADDED**: Advanced budget planning
+- ✨ **ADDED**: Recurring budget tracking
+- ✨ **ADDED**: Budget vs actual comparisons
+- ✨ **ADDED**: Budget alerts and notifications
+
+### UI/UX
+- 🎨 **ADDED**: Budget visualization charts
+- 🎨 **IMPROVED**: Budget management interface
+- 🎨 **ADDED**: Budget progress indicators
+
+### Technical
+- 🔧 **IMPROVED**: Budget calculation engine
+- 🔧 **ADDED**: Budget data validation
+- 🔧 **IMPROVED**: Performance for large datasets
+
+## [7.2.0] - 2024-08-XX
+
+### Features
+- ✨ **ADDED**: Multi-currency support
+- ✨ **ADDED**: Real-time exchange rates
+- ✨ **ADDED**: Currency conversion tools
+- ✨ **ADDED**: Multi-currency accounts
+
+### UI/UX
+- 🎨 **ADDED**: Currency selector interface
+- 🎨 **IMPROVED**: Transaction display with currencies
+- 🎨 **ADDED**: Exchange rate indicators
+
+### Technical
+- 🔧 **IMPROVED**: Currency handling
+- 🔧 **ADDED**: Exchange rate caching
+- 🔧 **IMPROVED**: Multi-currency calculations
+
+## [7.1.0] - 2024-07-XX
+
+### Features
+- ✨ **ADDED**: Enhanced chart types
+- ✨ **ADDED**: Interactive data visualization
+- ✨ **ADDED**: Custom chart configurations
+- ✨ **ADDED**: Export charts to images
+
+### UI/UX
+- 🎨 **IMPROVED**: Chart responsiveness
+- 🎨 **ADDED**: Chart animations
+- 🎨 **IMPROVED**: Chart accessibility
+
+### Technical
+- 🔧 **IMPROVED**: Chart rendering performance
+- 🔧 **ADDED**: Chart data caching
+- 🔧 **IMPROVED**: Chart interaction handling
+
+## [7.0.0] - 2024-06-XX
+
+### Breaking Changes
+- 💥 **CHANGED**: Complete UI redesign
+- 💥 **CHANGED**: New database schema
+- 💥 **CHANGED**: Updated API structure
+- 💥 **REMOVED**: Legacy features
+
+### Features
+- ✨ **ADDED**: Modern Material Design 3 interface
+- ✨ **ADDED**: New navigation system
+- ✨ **ADDED**: Enhanced transaction management
+- ✨ **ADDED**: Improved data organization
+
+### Technical
+- 🔧 **IMPROVED**: Complete codebase refactoring
+- 🔧 **ADDED**: New architecture patterns
+- 🔧 **IMPROVED**: Database performance
+- 🔧 **ADDED**: Better state management
+
+## [6.x.x] - 2024-05-XX and earlier
+
+### Legacy Versions
+- Previous versions used different versioning scheme
+- Major architectural changes in v7.0.0
+- Database migrations required for v7.0.0 upgrade
+
+---
+
+## Version Types
+
+### Major Releases (X.0.0)
+- Breaking changes
+- Major feature additions
+- Database schema changes
+- UI/UX redesigns
+
+### Minor Releases (X.Y.0)
+- New features
+- Performance improvements
+- Enhanced functionality
+- Backward compatible changes
+
+### Patch Releases (X.Y.Z)
+- Bug fixes
+- Security patches
+- Minor improvements
+- Documentation updates
+
+## Migration Notes
+
+### Upgrading to v7.5.1
+- No breaking changes
+- Security improvements recommended
+- Enhanced error handling
+- Better user experience
+
+### Upgrading to v7.0.0
+- **IMPORTANT**: Backup your data before upgrading
+- Database migration required
+- UI changes may require user adaptation
+- Some features may have moved or changed
+
+## Support
+
+For upgrade assistance:
+- Check the [Migration Guide](VERSIONING.md#migration-guide)
+- Review [Security Setup](README.md#security-setup)
+- Report issues on [GitHub](https://github.com/Sudoerz/IntelliCash/issues)
+
+---
+
+**Note**: This changelog follows the [Keep a Changelog](https://keepachangelog.com/) format and [Semantic Versioning](https://semver.org/) principles.