RFD 1087 details: the file map, write triggers, and the end-of-session checklist

Compacted. This RFD is abandoned, so its working-out was removed to keep the live corpus small. 1033 words are in git history and nothing was lost.

git show ac8201e2df493305313466c3764ce2cc2d88bdec:rfd/1087-gemini/DETAILS.md

The README beside this file is whole. It carries the state, the decision and the retraction, which is what a reader needs to know a road is closed and why.