Improve UI/UX of Share Post Screen

# Description:
Introduce a new Post Creation screen that draws inspiration from Instagram's clean and intuitive post UI. This screen will allow users to create and share posts with a visually appealing, modern interface that emphasizes ease of use and consistency with the app’s design language.

## Expected Features & Enhancements:

Clean layout inspired by Instagram's post flow (e.g., image preview, caption field, and share button)

Image selection with preview and optional caption input

Modern visual elements: smooth animations, rounded components, subtle shadows

Clear call-to-action for sharing posts

Consistent styling with the rest of the application

## Benefits:

Familiar and intuitive experience for users

Improved visual appeal and usability

Encourages user engagement through a streamlined posting flow

Maintains design consistency with modern social platforms