Singularity-Free Galactic Centers and Dark-Matter-Free Flat Rotation from Parity Conversion in Six-Throat Directed Geometry

This work develops a regular galactic-center parity-conversion mechanism within Six-Throat Directed Geometry and derives a source-driven exterior force that decreases as one over radius, producing a radius-independent contribution to circular speed. The resulting rotation law combines the baryonic contribution with one additional constant geometric contribution for each galaxy, while the dark-halo coefficient is fixed to zero. The model is tested against the full SPARC mass-model catalog. At R over Rmax greater than or equal to 0.75, the pre-specified quality sample contains 115 galaxies, with a median reduced chi-square of 0.2903 and a median model RMS of 2.236 kilometers per second. A single catalog-wide amplitude is strongly disfavored, selecting a galaxy-dependent conversion strength. An independent LeMMINGs VII compact 5 GHz cross-match gives a distance-controlled censored-rank coefficient of 0.78195, with a one-sided probability of 0.01287 and a two-sided probability of 0.03747. The archive includes the clean manuscript, public input tables, final analysis tables, figures, SHA-256 checksums, and a deterministic reproduction script that rebuilds the primary SPARC results and repeats the one-million-draw radio permutation calibration.