Low-Multipole Suppression from Distinguishable-History Capacity

We isolate a parameter-free route to large-angle CMB suppression within the Cosmochrony framework. The previous phenomenological low-$\\ell$ envelope of the white paper is replaced by a distinguishable-history mechanism. The central geometric input is the $S^3$ fibre decomposition, whose uniform moment split gives a fibre-to-base spectral stiffness ratio $8/3$ once the Born–Infeld saturation factor is included. The central low-$\\ell$ input is not a vanishing early growth rate, but the small absolute number of distinguishable projective histories at the first admissibility ranks. For the canonical Pell counting channel of the trajectory-branching note, \\[ {N_{\\mathrm{hist}}}(n)=\\frac{(1+\\sqrt{2})^{n+1}+(1-\\sqrt{2})^{n+1}}{2}, \\] so ${N_{\\mathrm{hist}}}(1)=3$, ${N_{\\mathrm{hist}}}(2)=7$, and ${N_{\\mathrm{hist}}}(3)=17$: large angular modes probe a regime with very few distinguishable histories, a bounded-history effect on the admissible large-angle power rather than an adjustable damping law. The companion projection-kernel note derives the Bessel envelope used below as the exact information-theoretic capacity ceiling of a complex Gaussian mode supported on $N$ distinguishable histories, carrying the entropy-to-power step as a conditional theorem chain; it bounds the power but does not prove saturation. A $2\\times2$ grid of parameter-free envelopes and angular dictionaries, anchored only by $n=1\\leftrightarrow\\ell=2$, is confronted with the Planck 2018 spectra without any fitting: on TT ($2\\le\\ell\\le30$) every cell improves on ${\\Lambda\\mathrm{CDM}}$, with diagnostic $\\chi^2$ dropping from $27.26$ to $17.70$ for the most directly derived cell (Bessel envelope with the H-dictionary); TE is neutral and EE mildly disfavoured, consistently with the fact that no dedicated low-$\\ell$ polarization transfer treatment is included at this stage. The envelope is a staircase in $\\ell$ (integer admissibility ranks), a distinctive discrete signature. The independent $8/3$ geometric witness is re-audited and predicts the separate modulation-scale ratio $\\sqrt{8/3}\\simeq1.633$.