fix: improve SQLite connection handling

[tusharmath]

SQLite Connection Improvements

This PR improves the SQLite connection handling and configuration to address database locking issues.

Changes

1. Restructured SQLite Module

• Created modular structure for better organization:
  • conn.rs: Connection configuration and customization
  • driver.rs: Core SQLite implementation
  • mod.rs: Public interface and trait definitions

2. Enhanced Connection Configuration

• Added customizable timeout settings
• Implemented connection pooling optimizations
• Added SQLite PRAGMA configurations:
  • WAL mode for better concurrency
  • Configurable busy timeout
  • Optimized synchronous mode

3. Improved Error Handling

• Better error context for database operations
• Clearer error messages for connection issues

4. Development Improvements

• Updated .gitignore to handle database and backup files
• Added tests for connection timeout configuration

Testing

• All existing tests pass
• Added new test for custom timeout configuration
• Manually verified database locking improvements

Related Issues

• Fixes database locking errors (#issue_number)

Future Improvements

• Consider adding connection retry logic
• Add monitoring for connection pool usage
• Add metrics for database operation timing