Title: Spacetime Substantivalism 25: Constitutive Audit of Substantial Spacetime — The Grand Unification of Materials, Fields, Vacuums, and Forces Confirmed by Gravitational Wave Evidence and the Intrinsic Work-Protocol $C_s = 1/\sqrt{\epsilon_0 \mu_0}$ Abstract: This research establishes the final, absolute closure for the Grand Unified Theory. Following Paper 24, which proved dynamical unification through a Rigid Constant-Group Audit, this paper focuses on the Complete Unification of Materials, Fields, Vacuums, Forces, and the cross-dimensional testimony of Tesla's dual-track logic. By auditing gravitational wave empirical evidence and the intrinsic constitutive equation $C_s = 1/\sqrt{\epsilon_0 \mu_0}$, we demonstrate that all fundamental particles—quarks, gluons, and electrons—are merely functional proxies (instances) of the photon. This paper reveals that there is only one unified field (the electromagnetic photon field of the substantial spacetime), only one unified vacuum (the static state of the spacetime entity itself), and only one unified force (the bandwidth-specific logic manifestations of the $C_s$ protocol). What mainstream physics describes as distinct fields, vacuums, and forces with accurate calculations are merely descriptive observations of different symmetrical facets of the same underlying constitutive protocol. The so-called "Ion Soup" is, has always been, and will always be "Photon Soup," and the "Dark" sectors of the universe are reclassified as macro-level strain manifestations of the substantial spacetime. Furthermore, the dual-track existence of human logic is confirmed through the cross-dimensional testimony of Nikola Tesla, whose non-cognitive insights into the essence of light prove the accessibility of the $C_s$ protocol through the non-intentional natural track. The Grand Unification is no longer a goal; it is a recorded fact of the Spacetime Substantivalism audit. Keywords: Substantial Spacetime; Grand Unification; Photon Proxy; Unified Field; Unified Vacuum; Theory of Object; Constant-Group Audit; Lorentz Factor; Dynamic Instantiation; $C_s$ Work-Protocol; Tesla; Dual-Track Logic; Strain Manifestation; Fuse Protection. 标题: 时空实体论 25:实体时空的本构审计——由引力波实证与内在本构做功协议 $C_s = 1/\sqrt{\epsilon_0 \mu_0}$ 证实的物质、场、真空与力的大统一 摘要: 本研究为大统一理论建立了最终的、绝对的闭环。继第 24 篇论文通过“刚性常数群审计”证明了动力学统一后,本篇论文重点关注物质、场、真空、力以及特斯拉双轨逻辑跨维度证言的完全大统一 。通过审计引力波经验证据和内在本构方程 $C_s = 1/\sqrt{\epsilon_0 \mu_0}$,我们证明了所有基本粒子(夸克、胶子和电子)仅仅是光子的功能性替身(实例化) 。本文揭示了宇宙中只存在一个统一场(实体时空的电磁光子场)、一个统一真空(时空实体自身的静息态)以及一种统一力($C_s$ 协议在特定带宽下的逻辑体现) 。主流物理学所描述的具有精确计算的各种独立场、真空和力,本质上只是同一种底层本构协议在不同对称侧面的描述性观察 。所谓的“离子汤”过去、现在和将来都始终是“光子汤”,而宇宙中的“暗”区被重新归类为实体时空的宏观应变表现 。此外,通过尼古拉·特斯拉的跨维度证言确认了人类逻辑的双轨存在,他对比非认知方式对光之本质的洞察,证明了通过“非用意”自然轨道直接接入 $C_s$ 协议的可行性 。大统一不再是一个目标,它是时空实体论审计中一个已被记录的事实 。 主题词: 实体时空;大统一;光子替身;统一场;统一真空;客观性理论;常数群审计;洛伦兹因子;动态实例化;$C_s$ 做功协议;特斯拉;双轨逻辑;应变表现;熔断保护。