V63: Photosynthesis as an Update-Continuity System — KPI Reversal, Variance-First Dynamics, and EM-Environment Benchmarking

We reinterpret photosynthesis not as an energy-generation mechanism but as an update-continuity system that sustains operation under discrete event accumulation. Building on the variance-stability framework developed in V61, we demonstrate that system failure is governed primarily by variance growth rather than mean reaction rates. Key findings:(1) Photosynthesis functions as an "exhaust system" rather than a "generator" — throughput is the primary function, and organic production is a byproduct of successful update continuity.(2) Water flow serves as the physical implementation of the Σ-operator, controlling both mean efficiency and variance stability through a single control parameter (flow velocity v ≈ 3 cm/s achieves both 7× efficiency gain and 1/7 variance reduction).(3) A paradigm shift in KPIs is required: from efficiency (%) to update-continuity metrics including entropy exhaust rate, bubble clearing index, and failure probability.(4) Known electromagnetic effects (cavity chemistry, polariton chemistry, Casimir effect) serve as benchmarks, leading to testable predictions that variance changes before mean reaction rate under varying EM environments. This variance-first perspective suggests that stability, not efficiency, is the primary organizing principle of living and self-operating systems. The framework positions biological organisms as "terminals of a dynamic universe" — local computational nodes that sustain update continuity under cosmic constraints. Part of the YAGC (Yoshida-AI-Generated Cosmology) Project series on Information-Philosophical Cosmology.