Curate improvements from open pull requests

[Dan Wahlin (DanWahlin)]

This pull request updates the README.md files to improve the presentation and clarity of course resources and lesson content. The most significant change is a major reorganization and visual enhancement of the "Other Courses" section in the main README.md. Additionally, minor formatting fixes were made to lesson content.

Improvements to course listings and documentation:

• The "Other Courses" section in README.md has been reorganized into themed groups (Azure, Edge, MCP, and Agents; Generative AI Series; Core Learning; Copilot Series) and now uses visually distinct badge-style links for easier navigation and improved readability.

Minor formatting and clarity fixes in lesson content:

• Fixed line breaks in the "Effort" descriptions for inventions in lessons/04-structured-output/README.md to ensure sentences are not awkwardly split and are easier to read. [1] [2]
• Removed an unnecessary code block marker from a sample JSON output section to clarify the formatting.