D5 (main loop on a context, DoRun returns) is implemented and measured:
387 passed with D5 on, identical failure set with D5 off. The §10 D5 entry
records the working-tree bisection of the remaining reds, none of them D5:
1. the WIP jump_fcontext->fiber_transfer libcontext change is not
behavior-preserving even dormant (kills nested baseline_fiber_alone;
passes with the file reverted to Phase A) - fix before the flip, and it
corrects this doc's earlier attribution of the WIP-tip failure to D;
2. the Phase A scoreboard is stale for coroutine-nested TODAY: at the
exact Phase A state it dies at fiber_yield_across_modal_close -
environment-sensitive, re-baseline before attributing;
3. races wakeup_during_transition flips with wx binary layout alone.
All three are the hot-main-swap-out wake-window class that C+B+E remove
structurally - expect those harnesses green AT the flip, not before.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LBjomQfKyRa3jBdeAKpmTw
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