Framework of Limit Unification and No-Observer Ontologization\\ \large Unified Time Scale, Boundary Time Geometry, and Consistent Variational Principle

In previous works, we have characterized the ``Universe'' as a maximal, consistent, and complete ontological mathematical object, internally containing multiple layers of components such as causal manifolds, unified time scale, boundary time geometry, bulk quantum field theory, scattering and spectral shift theory, Tomita--Takesaki modular structure, and generalized entropy. Under this framework, an integrated description of time, causality, entropy, and observation can be achieved, but ``physical laws themselves'' and ``physical details'' (gauge groups, field content, mass spectrum and couplings, fluid and many-body effective equations, etc.) mostly appear as external additions. This paper proposes a framework of **limit unification completely independent of any observer ontological concept**: we take unified time scale and boundary time geometry as the sole fundamental geometric--spectral structures, unifying all physical laws into necessary conditions of a single consistent variational principle. Specifically: 1. Introducing the scale identity in scattering theory equation \kappa(\omega) =\varphi'(\omega){\pi} =\rho_{rel}(\omega) =1{2\pi}trQ(\omega), equation unifying scattering phase derivative, relative density of states, and Wigner--Smith group delay trace into a unique time scale mother ruler. 2. Introducing total connection in boundary time geometry equation \Omega_\partial =\omega_{LC}\oplus A_{YM}\oplus \Gamma_{res}, equation unifying gravity, internal gauge fields, and resolution/renormalization group flow into a single geometric object on the boundary bundle. 3. Introducing generalized entropy on small causal diamonds equation S_{gen}(D) =A(\partial D){4G\hbar} +S_{bulk}(D), equation and constructing a global consistency functional equation \mathcal I[\mathfrak U] =\mathcal I_{grav} +\mathcal I_{gauge} +\mathcal I_{QFT} +\mathcal I_{hydro}, equation where each term constrains consistency at geometric--entropy, gauge--topological, quantum--scattering, and coarse-grained fluid levels respectively. The main result of this paper is: under natural assumptions of causality, unitarity, and entropy stability, applying the unified consistency principle equation \delta\mathcal I[\mathfrak U]=0 equation to the Universe Ontology Object \mathfrak U, the necessary conditions are respectively equivalent to: 1. Geometric variation in the limit of small causal diamonds yields Einstein equations equation G_{ab}+\Lambda g_{ab} =8\pi G\langle T_{ab}\rangle, equation along with appropriate quantum energy conditions and focusing conditions; 2. Under fixed K-theory class conditions, variation of boundary channel bundle and total connection yields Yang--Mills equations and gauge field anomaly cancellation conditions, thereby unifying ``field content and gauge groups'' as consistency equations of boundary K class and scattering K^1 class; 3. Under given geometric and gauge background, variation of relative entropy functional for bulk states and scattering data yields Wightman axioms, Euler--Lagrange field equations, and Ward identities of local quantum field theory, meaning QFT is no longer an independent input but an inevitable result of the unified consistency principle at the quantum--scattering level; 4. In long-wavelength and low-resolution limits, variation of resolution connection and macroscopic conserved currents yields generalized Navier--Stokes type fluid equations and diffusion equations, unifying macroscopic irreversible dynamics as gradient flows of generalized entropy on the unified time scale. Therefore, without introducing any ``observer ontology'' concept, this paper achieves ``limit unification'' in physics: General Relativity, Gauge Field Theory, Local Quantum Field Theory, Fluid Dynamics, and Many-Body Effective Dynamics are all necessary conditions of the same cosmic consistency variational principle under different resolutions and boundary conditions, while all ``physical details'' are unifiedly encoded in boundary K-theory classes and scattering analytic invariants.