docs: align README footer with cutandmove-showcase brand pattern

- Add italic "Powered by MILL5 / MVP / podcast / support" footer block
  mirroring the cutandmove-showcase style
- Insert Visual Studio Code and GitHub callouts alongside the Microsoft
  MVP reference in both Related Links and the italic footer
- Add a brand coda line above the footer
- Remove the self-referential "Powered by [Days on Purpose]" line;
  attribute to MILL5 instead