C121 — Both phases of the Conquest 3K+8K refinement

All seven native interior comparisons retain the exact3K+8K decomposition on both components. The generated middle field reverses its BC labels as the reflected Conquest field advances:

For example, the first row has same-side difference1587 and cross-axis component sums 2834+1399−1=2833+1400−1=4232. The full width is5819. Exact quarter-year proof coordinates confirm the same results, with no civil year zero.

The reflected1406 closing pair instead uses 2827t/2826n BC → AD1406t/1407n for8K. Its11K origin would be 4414t/4413n BC, the conditionally generated closing pair. Native 4415t/4414n BC remains one year too early for exact11K to that target, on both components.

C11 already established the seven native memberships and the compression boundary. C121 checks only their new8K insertion and phases; it does not rerun C11’s whole endpoint campaign. No generated preimage becomes a historical source event by this calculation.

68 checks passed; C120 graph unchanged. Next: insert these boundaries into the four retained11+2=13 Creation–Conquest–Flood paths. High sufficient.