Enhances event layout engine with advanced rendering logic

Introduces sophisticated event layout algorithm for handling complex scheduling scenarios

Adds support for:
- Grid and stacked event rendering
- Automatic column allocation
- Nested event stacking
- Threshold-based event grouping

Improves visual representation of overlapping and concurrent events

src/v2/core/IGridConfig.ts

@@ -3,4 +3,5 @@ export interface IGridConfig {
   dayStartHour: number;    // e.g. 6
   dayEndHour: number;      // e.g. 18
   snapInterval: number;    // minutes, e.g. 15
+  gridStartThresholdMinutes?: number;  // threshold for GRID grouping (default 10)
 }