[2.0 / next] A memo that probed isPending once lets a later sync write break free of the hold #4699

Ruled-not-built row S-50 from #4695. The ruling is in packages/web/test/async-gen/rulings/S-50.ts. Rule: D-25. Decision 1 in documentation/plans/optimism-seam-spike-brief.md §8 withdraws the paragraph "a verdict posture outlives the pass that asked".

Shape: m = 1 + k + (probe ? isPending(x) : 0) + x. An action holds x = 1 while m probes. Then probe is turned off and a sync write to k re-runs m.

Ruled: the re-run probes nothing, so its read of x is a plain read of the held staging. m is the hold's work, and the tick that wrote k holds with it until the body returns (vm0:3 vs1:1).

Today: the screen publishes vm0:2 vs1:1, twice. The sticky verdict bit from the previous run makes m read x as the screen's value, so k breaks free.