A UV-anchored budget-partition mechanism for derived-Λ within flux-fixed GR

This record releases v2.0.0 of A UV-anchored budget-partition mechanism for derived-Λ within flux-fixed GR. It presents a UV-anchored candidate mechanism for the dimensionless variable x = Λ / Λ_obs on the GR-exact, flux-fixed branch of the Gauged Constant Vacuum-Mode (GCV) framework. The analysis treats the audited v6 capability-conditioned posteriors (MEASURE/DETECT) as fixed late-time inputs and applies a fixed imported acceptance gate from the companion three-bottleneck closeout note. The UV prior is modeled as a tadpole-bounded budget-partition / overlap-share prior on a high-dimensional flux lattice, with effective overlap rank d_scan. For the KS/Whitney benchmark corner (L = 3332, K = 1968, n_eff^2 = 317) and benchmark d_scan ≈ 192, the UV-reweighted posteriors satisfy the imported Target gate across all 8 public v6 analysis variants. This release includes the new geometry-closure result. A population scan of the CQSV orientifold database defines a geometry-derived overlap proxy d_proxy = S × M, where S is the orientifold support-sector count extracted from OP and M is an internal multiplicity extracted from OPC[5]. Across 24,128 explicit orientifold embeddings, d_proxy has p10/p50/p90 = 64 / 200 / 252. An independent UV d-sensitivity scan selects a narrow Target-pass window d_pass = [178, 206] (step-2 scan on d = 160, 162, ..., 230; contiguous pass set 178, 180, ..., 206) across all 8 public v6 variants. The UV-required window therefore lies within the geometry-populated band, and the benchmark d_scan ≈ 192 lies near the CQSV population median. This release provides a population-level geometry closure rather than a single-embedding topological derivation of the overlap rank. In this sense, geometry supplies the available overlap-dimension scale, while the UV mechanism selects a viable operational window within that scale. Contents: manuscript PDF and LaTeX source; machine-readable gate-metric tables; minimal v6 posterior CSV grids required for reproduction; CQSV geometry-closure tables; the UV d-sensitivity scan table; and Python scripts that reproduce the gate metrics and regenerate the geometry-closure summary and figures into a separate generated/ directory without modifying the archived files. Project homepage:https://johansson.digital Project overview hub:https://github.com/gcv-framework/gcv-vacuum-energy