Replace the implicit pro-rata RSU/cash split with an explicit flat
47% marginal (45% PAYE + 2% NI) for the RSU vest tax stack. The orange
slice now scales linearly with rsu_vest instead of wobbling around the
month's effective PAYE rate; cash PAYE/NI slices have those amounts
subtracted out so the stack still totals to actual deductions.
Affects panel 7 (monthly), panel 12 (YTD cumulative), panel 7
(YTD uses), and the Sankey panel. Verified on 35 months of live data:
sum invariant holds exactly (cash + rsu_marginal + cash_ni ==
income_tax + national_insurance), no negatives in cash slices.
Out of scope (left raw): effective-rate %, data-integrity, payslip
table, P60/HMRC reconciliation — those are audit views that use
unmodified income_tax / cash_income_tax columns.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
cb3ffa6d8d