Approved-but-not-executed plan to collapse the two-user model
(left4me + l4d2-sandbox) into one. The build-time-idmap that
translates sandbox writes back to left4me uid becomes a no-op when
source uid == target uid, so it's removed along with ~30 lines of
helper plumbing. Hardening already covers the same-uid attack
surface the sandbox uid was defending against, so collapsing makes
the architecture consistent with the web/server hardening-only
decision.
Plan: docs/superpowers/plans/2026-05-15-uid-collapse.md
Handoff: docs/superpowers/specs/2026-05-15-session-handoff.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
