Adds a "Compare to prior period" toggle to the Sales report header.
When on, the API recomputes the KPI window for the equal-length window
immediately preceding the selected range (previousPeriodBounds) behind
`?compare=1`, and the five window-derived KPI tiles (Won, Lost, Win
rate, Avg time-to-close, New leads) render colour-correct "vs prior"
deltas. Point-in-time tiles (Active interests, Pipeline value) have no
prior-window analogue and intentionally show no delta. The prior-window
query runs in parallel with the main batch and resolves to null when the
toggle is off (zero cost). Toggle state persists in the saved-template
config.
Closes the spec's "period comparison on every report" gap for Sales;
Operational already rendered period-start deltas.
Pure helpers TDD'd: previousPeriodBounds (range.ts) +
computeSalesKpiComparison (sales-comparison.ts), 7 unit tests. tsc +
lint clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Matt
681b94a8ef