Phase 1: Home UI Migration

[ryansoe]

Changes

• Migrated app/(tabs)/index.tsx from raw React Native primitives to Tamagui (Screen, Card, YStack, XStack, AppText,
  SectionTitle). Removed all hardcoded colors and StyleSheet blocks; background now uses $primary token.
• Migrated components/Graphs/PieChart.tsx layout wrapper to Tamagui YStack. Replaced the SVG center label with an
  absolutely-positioned AppText so the font matches the rest of the app.
• Migrated components/NewTransaction/NewTransactionButton.tsx layout to Tamagui (XStack, AppText, AppInput, AppButton). Added forceOpen/onForceOpenHandled props to allow external triggering from Quick Actions.
• Created components/Home/QuickActionsSection.tsx — row of three QuickActionCard primitives (Add Expense, History, Goals).
• Created components/Home/WeeklySpendingSection.tsx — SegmentedControl (1D / 1W / 1M / 1Y) with a StatCard that filters transactions by the selected period and displays the corresponding total.

Testing

• Manually verified in browser: Home screen loads, pie chart renders with correct category slices and
  native-font center label, period selector updates the spending total, Quick Actions cards navigate to the correct tabs and
  trigger the transaction form.

Tracking

Add your issue number below.

Resolves #