views/month-view-row: Compute exact width of event widgets
Currently, month cells are using round() to allocate the width, whereas event widgets are using implicit double → int conversion, which causes event widgets to be offset by a pixel, and thus touches month cells' borders.
This new approach guarantees the exact width of the event widgets by invoking round().
Before:
Screencast From 2025-12-09 22-42-28.mp4
After (Screen recording taken in high contrast and large text for visibility):
Edited by Hari Rana