Accept Implemented ADR

Move an implemented ADR from feature folder to docs/adr/ as accepted documentation.

Usage: When user says "accept ADR for {feature-name}" or provides {feature-name} {adr-filename}

Instructions

1. Verify implementation is complete: The feature described in the ADR should be implemented and working

2. Read the proposed ADR from docs/features/{feature-name}/{adr-filename}.md

3. Final trim pass - Remove any content that's not needed for documentation:

   • No implementation notes or TODOs
   • No phase tracking or status checklists
   • Keep only: Context, Decision, Consequences
   • Ensure it's concise (fits on one screen ideally)