feat: Implement event creation/editing page and related components
This MR adds the event creation/editing page.
New Features:
Implemented the main event page.
Created new DatePicker and TimePicker components.
Fixes & Refinements:
Adjusted Dropdown and Font components (color, size, cursor).
Implemented auto-sizing for EventColor, ImageCard, and TextField components.
Fixed a real-time color change bug in EventColor.