Fixed multiple issues with relative weight sliders:
1. Sanitize focusData on load (ensure all 6 fields are numeric)
2. Sync focusTemp when clicking "Anpassen" button
3. Robust sum calculation filtering only *_pct fields
4. Convert NaN/undefined to 0 in all calculations
5. Safe Number() coercion before normalization
Fixes errors:
- "Gewichtung gesamt: NaN"
- "Input should be a valid integer, input: null"
- Prozent always showing 0%
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>