V.R264 — The Wick rotation is a chart operation

In orthodox QFT, the Wick rotation t -> -i tau_E is a formal device with unclear physical justification. In tau, the Wick rotation is a chart operation: a change of projection from the Minkowski chart to the Euclidean chart. Both charts are readouts of the same boundary algebra H_partial[omega]. The ambiguity is resolved structurally.