Issue-17: add url override to post block

[nikkifurls]

Description

This PR adds a URL override feature to the Post block, allowing users to specify a custom URL with analytics tracking parameters, etc. The override is stored in attributes and used on the front end instead of the post URL.

Related to Issue #17: add url override to post block

Changes

• Added a new attribute for storing the URL override
• Modified the Post block to use the URL override if provided
• Updated frontend rendering to use the URL override if available

Testing

1. Create a new Post block and add a custom URL in the URL override field
2. Verify that the custom URL is used on the frontend instead of the post URL
3. Verify that the custom URL is properly saved in attributes
4. Remove the custom URL and verify that the post URL is used on the frontend instead

[mogmarsh]

looks great - just update the version here and add an entry to the changelog. Once you do that, it will cut a release when you merge it. 👍