Remove outdated documentation and cursor rules for workspace lockfile plugin

[Cellule]

A lot of the documentation was AI generated. I did a pass to clean stuff up a bit.

• Removed work in progress
• Removed too verbose development instruction
• Removed usage with dependabot as we haven't been able to make that work
• Removed Cursor rules, they were not written in a way that gave any value
• Removed Implementation steps, most of it is done and now tracking issues in github issues directly

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This change is