Mark project as archived and update README

[DavePearce]

Updated README to indicate project is archived and redirect users to go-corset.

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Note

Marks the project as archived and restructures README.org with an archive notice, redirect to go-corset, and normalized section headings.

• Documentation:
  • Archive notice: Add Status: Archived to README.org with a redirect to go-corset.
  • Structure: Normalize and deepen heading levels (e.g., How to contribute, Installation, Usage, CLI and concepts, programming sections) for clearer hierarchy.
  • Content: Keep existing usage/CLI details while repositioning under updated headings.

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