Added logic for creating posts

[barrera77]

1. Created useCreatePost hook

• Handles form validation.
• Sends POST request to API.
• Redirects after success.
• Manages errors and loading state.

2. Updated New Post page

• Uses useCreatePost instead of inline submission logic.
• Auto-generates id (UUID) and slug.
• Formats createdDate for input.

3. Fixed redirection after post creation

• Redirects to post page or posts index instead of trying to read missing fields from response.

4. Posts index page

• Fetches posts via getStaticProps.
• Displays posts in a list.
• Includes “Create New Post” link to the new post page.