We compute the one-loop effective action for the metric obtained by integrating out the stochastic fluctuations of the Onsager—Machlup (OM) probability fluid on a curved spin manifold. The OM action describes 9 internal degrees of freedom: density amplitude, phase, Lorentz rotor (6 bivector components), and Takabayasi angle. Expanding to second order around the classical vacuum and applying the Schwinger—DeWitt heat kernel expansion, we derive the Seeley—DeWitt coefficients au2080 = 9 and au2081 = (7/4)R − 10m², where R is the Ricci scalar and m the particle mass. Three features are essential: (i) the cross-coupling between density and phase fluctuations generates an effective gauge connection contributing +4m² to the scalar sector; (ii) an algebraic mass cancellation renders density fluctuations massless; and (iii) the rotational kinetic term generates the Bochner Laplacian (not Hodge—de Rham), so the Weitzenböck curvature endomorphism is absent (κ = 0). The positive coefficient 7/4 ensures that the induced Newton constant G_ind = 8πℏ²/(7m²c²) is positive (attractive gravity). This is a signature of the Clifford-algebraic structure of the OM framework.