feat(THI-51): modernize revenue & expenses tab - #21

Summary

Rebuilds the Revenue & Expenses tab around the THI-45/46 design system with a 2-column (1fr + 340px) sticky layout, plus a new <SeasonalBars> primitive.

New primitive

• shared/SeasonalBars.tsx — 12-bar SVG chart with peak-month color differentiation (accent for peak, ink-3/50% for off-peak). Exports derivePeakMask(peakMonths) that centers N peak months around July.

Main column (STR)

• Segmented rental-type switcher replaces the old sky / violet pill buttons
• FormSection: Revenue — nightly rate, cleaning fee, stay length, rental delay, platform fee %, property mgmt %
• Occupancy panel — Toggle for seasonal mode; when on: Peak Months / Peak Occupancy / Off-Peak Occupancy / Weighted Effective sliders + <SeasonalBars> showing the implied 12-month profile. Advanced <details> exposes the existing MonthlyProfileEditor for per-month overrides.
• FormSection: Operating Expenses (8 fields) — cleaning cost / turn, utilities, supplies, marketing, software, lawn & snow, other monthly, insurance (annual)
• FormSection: Reserves (3 SliderFields) — maintenance / capex / damage
• FormSection: Professional Fees — accounting, legal
• <details> Vermont tax configuration (collapsible) — 5 % fields + registration fee + Platform Remits Tax <Toggle>
• <details> Growth & Exit (collapsible, shared fields)

LTR

Mirrors the STR structure with lease-focused revenue (monthly rent, lease duration, pet rent, late fee, vacancy rate, lease-up), 8 operating expenses, 2-slider reserves, and the shared Growth & Exit block.

Sticky preview aside

Border-rule card showing Monthly Revenue, Monthly Expenses, Monthly Cashflow fetched from getResults / getLTRResults. Refreshes on mount and after every save. Positive cashflow in accent tone; negative in negative tone.

Preserved behavior

• STR ↔ LTR swap
• Shared-field sync between STR and LTR forms
• Dual-persistence save (active type first, then shared to the other)
• MonthlyProfileEditor (now under Advanced disclosure; token-ified colors)
• All callback props from the detail shell unchanged — RevenueExpensesTab only gains a new propertyId prop, threaded through in PropertyDetail.tsx

Scope notes

• The rewrite drops most inline tooltips in favor of the cleaner FormSection subtitles; fields still accept the tooltip prop via CurrencyInput / PercentInput where useful (tooltip copy preserved in the file — can re-surface via hint prop in a polish follow-up).
• Seasonal model exposed to the UI for the first time (was in STRAssumptions but not editable before THI-51).

Test plan

• npm run build — passes, CSS 54.19 kB, JS 464.21 kB (-8 kB from dead-code elimination), 117 modules
• Dev run: STR scenario — toggle seasonal, drag peak months / peak / off-peak sliders, SeasonalBars redraws with accent/ink-3 peaks
• Advanced disclosure opens the monthly profile editor; templates load; per-month edits persist
• Switch to LTR — left column swaps fields, shared fields (growth / exit / insurance / etc.) stay in sync after save
• Save: preview aside refreshes with new monthly revenue / expenses / cashflow
• VT tax collapsible opens/closes; Platform Remits Tax toggle updates state
• Dark mode: all FormSections, sliders, SeasonalBars, preview card token-driven

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