feat(miniapp): refine UI and add utility bill management

- Fix collapsible padding and button spacing
- Add subtotal to balance card
- Add utility bill management for admins
- Fix lints and type checks across the monorepo
- Implement rejectPendingHouseholdMember in repository and service

apps/miniapp/src/lib/ledger-helpers.ts

@@ -0,0 +1,234 @@
+/**
+ * Pure helper functions extracted from App.tsx for ledger, member, and draft operations.
+ * No side-effects, no framework imports — just data transformations.
+ */
+
+import { majorStringToMinor, minorToMajorString } from './money'
+import type {
+  MiniAppAdminCycleState,
+  MiniAppDashboard,
+  MiniAppMemberAbsencePolicy,
+  MiniAppMemberAbsencePolicyRecord,
+  MiniAppAdminSettingsPayload
+} from '../miniapp-api'
+
+/* ── Draft types ────────────────────────────────────── */
+
+export type UtilityBillDraft = {
+  billName: string
+  amountMajor: string
+  currency: 'USD' | 'GEL'
+}
+
+export type PurchaseDraft = {
+  description: string
+  amountMajor: string
+  currency: 'USD' | 'GEL'
+  splitMode: 'equal' | 'custom_amounts'
+  splitInputMode: 'equal' | 'exact' | 'percentage'
+  participants: {
+    memberId: string
+    included: boolean
+    shareAmountMajor: string
+    sharePercentage: string
+  }[]
+}
+
+export type PaymentDraft = {
+  memberId: string
+  kind: 'rent' | 'utilities'
+  amountMajor: string
+  currency: 'USD' | 'GEL'
+}
+
+/* ── Pure helpers ───────────────────────────────────── */
+
+export function absoluteMinor(value: bigint): bigint {
+  return value < 0n ? -value : value
+}
+
+export function memberBaseDueMajor(member: MiniAppDashboard['members'][number]): string {
+  return minorToMajorString(
+    majorStringToMinor(member.rentShareMajor) + majorStringToMinor(member.utilityShareMajor)
+  )
+}
+
+export function memberRemainingClass(member: MiniAppDashboard['members'][number]): string {
+  const remainingMinor = majorStringToMinor(member.remainingMajor)
+
+  if (remainingMinor < 0n) {
+    return 'is-credit'
+  }
+
+  if (remainingMinor === 0n) {
+    return 'is-settled'
+  }
+
+  return 'is-due'
+}
+
+export function ledgerPrimaryAmount(entry: MiniAppDashboard['ledger'][number]): string {
+  return `${entry.displayAmountMajor} ${entry.displayCurrency}`
+}
+
+export function ledgerSecondaryAmount(entry: MiniAppDashboard['ledger'][number]): string | null {
+  if (entry.currency === entry.displayCurrency && entry.amountMajor === entry.displayAmountMajor) {
+    return null
+  }
+
+  return `${entry.amountMajor} ${entry.currency}`
+}
+
+export function cycleUtilityBillDrafts(
+  bills: MiniAppAdminCycleState['utilityBills']
+): Record<string, UtilityBillDraft> {
+  return Object.fromEntries(
+    bills.map((bill) => [
+      bill.id,
+      {
+        billName: bill.billName,
+        amountMajor: minorToMajorString(BigInt(bill.amountMinor)),
+        currency: bill.currency
+      }
+    ])
+  )
+}
+
+export function purchaseDrafts(
+  entries: readonly MiniAppDashboard['ledger'][number][]
+): Record<string, PurchaseDraft> {
+  return Object.fromEntries(
+    entries
+      .filter((entry) => entry.kind === 'purchase')
+      .map((entry) => [
+        entry.id,
+        {
+          description: entry.title,
+          amountMajor: entry.amountMajor,
+          currency: entry.currency,
+          splitMode: entry.purchaseSplitMode ?? 'equal',
+          splitInputMode: (entry.purchaseSplitMode ?? 'equal') === 'equal' ? 'equal' : 'exact',
+          participants:
+            entry.purchaseParticipants?.map((participant) => ({
+              memberId: participant.memberId,
+              included: participant.included ?? true,
+              shareAmountMajor: participant.shareAmountMajor ?? '',
+              sharePercentage: ''
+            })) ?? []
+        }
+      ])
+  )
+}
+
+export function purchaseDraftForEntry(entry: MiniAppDashboard['ledger'][number]): PurchaseDraft {
+  return {
+    description: entry.title,
+    amountMajor: entry.amountMajor,
+    currency: entry.currency,
+    splitMode: entry.purchaseSplitMode ?? 'equal',
+    splitInputMode: (entry.purchaseSplitMode ?? 'equal') === 'equal' ? 'equal' : 'exact',
+    participants:
+      entry.purchaseParticipants?.map((participant) => ({
+        memberId: participant.memberId,
+        included: participant.included ?? true,
+        shareAmountMajor: participant.shareAmountMajor ?? '',
+        sharePercentage: ''
+      })) ?? []
+  }
+}
+
+export function paymentDrafts(
+  entries: readonly MiniAppDashboard['ledger'][number][]
+): Record<string, PaymentDraft> {
+  return Object.fromEntries(
+    entries
+      .filter((entry) => entry.kind === 'payment')
+      .map((entry) => [
+        entry.id,
+        {
+          memberId: entry.memberId ?? '',
+          kind: entry.paymentKind ?? 'rent',
+          amountMajor: entry.amountMajor,
+          currency: entry.currency
+        }
+      ])
+  )
+}
+
+export function paymentDraftForEntry(entry: MiniAppDashboard['ledger'][number]): PaymentDraft {
+  return {
+    memberId: entry.memberId ?? '',
+    kind: entry.paymentKind ?? 'rent',
+    amountMajor: entry.amountMajor,
+    currency: entry.currency
+  }
+}
+
+export function defaultCyclePeriod(): string {
+  return new Date().toISOString().slice(0, 7)
+}
+
+export function defaultAbsencePolicyForStatus(
+  status: 'active' | 'away' | 'left'
+): MiniAppMemberAbsencePolicy {
+  if (status === 'away') {
+    return 'away_rent_and_utilities'
+  }
+
+  if (status === 'left') {
+    return 'inactive'
+  }
+
+  return 'resident'
+}
+
+export function resolvedMemberAbsencePolicy(
+  memberId: string,
+  status: 'active' | 'away' | 'left',
+  settings?: MiniAppAdminSettingsPayload | null
+): MiniAppMemberAbsencePolicyRecord {
+  const current = settings?.memberAbsencePolicies
+    .filter((policy) => policy.memberId === memberId)
+    .sort((left, right) => left.effectiveFromPeriod.localeCompare(right.effectiveFromPeriod))
+    .at(-1)
+
+  return (
+    current ?? {
+      memberId,
+      effectiveFromPeriod: '',
+      policy: defaultAbsencePolicyForStatus(status)
+    }
+  )
+}
+
+/**
+ * Compute the prefill amount for a payment based on member dues.
+ * Bug #5 fix: Prefill with the remaining amount for the selected payment kind.
+ */
+export function computePaymentPrefill(
+  member: MiniAppDashboard['members'][number] | null | undefined,
+  kind: 'rent' | 'utilities'
+): string {
+  if (!member) {
+    return ''
+  }
+
+  const rentMinor = majorStringToMinor(member.rentShareMajor)
+  const utilityMinor = majorStringToMinor(member.utilityShareMajor)
+  const remainingMinor = majorStringToMinor(member.remainingMajor)
+
+  if (remainingMinor <= 0n) {
+    return '0.00'
+  }
+
+  // Estimate unpaid per kind (simplified: if total due matches,
+  // use share for that kind as an approximation)
+  const dueMinor = kind === 'rent' ? rentMinor : utilityMinor
+  if (dueMinor <= 0n) {
+    return '0.00'
+  }
+
+  // If remaining is less than due for this kind, use remaining
+  const prefillMinor = remainingMinor < dueMinor ? remainingMinor : dueMinor
+  return minorToMajorString(prefillMinor)
+}