OpenVolleyScout 0.18

Release 0.18.

Changes included:

• bump app metadata to 0.18 across npm, Tauri and app constants
• restore player-performance heatmap rendering for numeric DataVolley zones
• keep start-zone markers on the left court and landing heatmap on the right court
• add player analytics refinements for serve/reception point conversion and other touches

Validation:

• npm run build
• npm test