v4.3.4 - StatisticsBuilder for incremental sum calculation

Changes

• New statistics_builder.py module with StatisticsBuilder class
• Implements proper incremental sum pattern: sum = last_db_sum + hourly_value
• Automatically filters already-imported points to avoid duplicates
• Tested and verified on LAB environment for ~14 hours

Fix Details

This release fixes dashboard spike issues by:

1. Removing state_class from statistics sensors (prevents HA auto-aggregation)
2. Using manual �sync_import_statistics with proper incremental sums
3. Pattern adopted from thedeemling/hass-energa-my-meter implementation

Upgrade Notes

After updating, you may want to clear existing statistics for the affected sensors (sensor.xxx_zuzycie, sensor.xxx_oddanie) if you see spikes in the Energy Dashboard.