Subjectivity-Intersection Braid Quantum Gravity: A Constructive Refutation of Objectivist Primacy from Source-Derived Quantum Dynamics to the Einstein Limit

We develop Subjectivity-Intersection Braid Quantum Gravity as a source-explicit mathematical quantum-gravity candidate in which a public Lorentzian spacetime carrier is generated by intersections of nonidentical, standpoint-bearing pointed-Braid processes. Version 0.91 retains the complete v0.9 finite Lorentz parent, four-component Ward identity, scoped Einstein equation G=(3/5)T, two-helicity spin-2 limit, derived matter-sector construction, calibration boundary, AF/quasi-local all-refinement channel, rank-three constraint closure, anisotropic UCP carrier, and all-finite-iteration backreaction. It adds a finite quantum reconstruction and control analysis through BGCE491. The actual oriented three-history cycle generates a 36-dimensional complex carrier; source reversal and cup/cap counting yield normalized squared-norm probabilities in the declared projective class; and retained source morphisms generate an exact Z2 superselection and observable algebra M18(C) direct-sum M18(C). Canonically compressed source controls define a six-order mixed-unitary CPTP engine. A typed source-word extension supplies exact LCU block encodings, a four-probability control solder, a raw-source signal qubit, and exact heralded actuation for all 32 sector/control cases. The first Lagrange black-box route retains a 10^23.14 to 10^44.43 query NO-GO. A source-compatible Chebyshev conversion instead gives exact deterministic circuits using 203 to 39,102 block-encoding queries, and hermitianization of the existing source-word LCU unitary removes explicit square-root-defect and spectral-read primitives. The construction is scoped: ordinary flip also generates a complex sector, the typed selector and success-address mark are explicit extensions, no hardware has executed the engine, and no competitor-divergent gravity-apparatus measurement has been performed. No empirical validation of quantum gravity is claimed.