Replace SQLite-specific functions with database-agnostic expressions to support
MySQL, SQLite, PostgreSQL, and SQL Server across all Filament dashboard widgets.
- Fix strftime() date formatting in SubscriptionMetrics, RevenueMetrics, and TrialPerformance
- Fix CAST AS REAL syntax in ChurnAnalysis widget
- Add getDateFormatExpression() method for date function compatibility
- Add getCastExpression() method for CAST syntax compatibility
- Support MySQL/MariaDB, SQLite, PostgreSQL, and SQL Server drivers
- Maintain identical functionality across all database types
Fixes multiple SQLSTATE[42000] syntax errors when using MySQL/MariaDB databases.
e60973c391