docs: add uninstall section to README

README.md

@@ -20,6 +20,12 @@ When the workflow itself or the underlying manifest format
 changes, re-seed from the platform repo by running
 `scripts/bootstrap-distribution-repos.sh`.
 
+## Uninstall
+
+To remove the package, run `scoop uninstall chain` (add `--purge`
+to also drop its cached data and persisted state). To stop
+tracking this bucket entirely, run `scoop bucket rm fai`.
+
 Issues, PRs, and ad-hoc questions belong at
 `https://git.flemming.ai/fai/platform` — this repo is intentionally
 quiet.