[MST-EUT Theory Series #21] First-Principles Derivation of the Fine-Structure Constant - 精細結構常數的第一性原理推導 (v2.1-zh)

This document constitutes Series #21 of the MST–EUT Theory Series and completes the first-principles derivation of the fine-structure constant α within the Mass–Space–Time Entanglement Unified Theory (MST–EUT). The derivation is based on three minimal ingredients: vacuum spectral selection, topological quantization of closed entropic flows, and a minimal observability threshold approximation. All quantities are traced back to the ontological constants (κ₀, α₀, O₀), without using empirical α, electric charge, or CODATA inputs. This work establishes a closed, dimensionally consistent, and falsifiable foundation for α as a structural invariant. 本文為 MST–EUT 理論系列第 21 篇,完成精細結構常數 α 的第一性原理封閉推導。推導僅依賴三個最小要素:真空譜化選態原理、封閉熵流拓撲量子化規範,以及可觀測性門檻的最小回應近似。所有量皆可追溯至本體論常數 (κ₀, α₀, O₀),不使用實驗 α、電荷 e 或 CODATA 常數表。本文確立 α 為一個具備量綱自洽性與可證偽性的結構不變量,完成 MST–EUT 對精細結構常數的第一性封閉。