Gravitational Manipulation Theory v1.2: Weak-Field Phenomenology, Environmental Screening, and an Observational Constraint Framework

Building on the self-consistent field solutions established in GMT v1.1, this work develops the weak-field phenomenology of Gravitational Manipulation Theory (GMT) and establishes a framework for confronting those solutions with observations. The coupled scalar–metric system is expanded about a v1.1 self-consistent background to derive the effective Newtonian coupling, gravitational slip, PPN parameters, and the master weak-field parameters (αGMT,λGMT). An environmental-screening trajectory is introduced to connect environment-dependent effective mass and interaction range with the recovery of the general-relativistic weak-field regime. Solar-System/PPN, fifth-force (Yukawa), and equivalence-principle channels are organized on a common GMT master plane and combined into an observational admissibility framework,PGMT=Pphys∩Psol∩Pobs. Epistemic status: GMT v1.2 presents an observational constraint mapping framework, not a verified observational exclusion of GMT parameter space. The constraint maps are schematic and model-dependent. Measured experimental values, confidence levels, verification of observable-to-parameter mappings, and calibrated parameter inference are deferred to GMT v1.3. The work explicitly maintains the distinctions [Constrained] ≠ [Validated] and Allowed ≠ Detected ≠ Confirmed.