Implement banking system features and enhancements

- Added banking mode with checking, savings, and charity accounts, including auto-split options for income.
- Introduced banking transaction management, including transfers and charity outflows.
- Updated family settings to allow configuration of banking features and interest rates.
- Enhanced data export functionality to include bank transactions.
- Improved user interface to display banking information and donation goals.
- Updated documentation to reflect new banking features and settings.

includes/family_settings.php

@@ -30,6 +30,12 @@ function familySettingsDefaultsRaw(): array {
         'currency_symbol' => '★',
         'currency_name' => 'Stars',
         'currency_permanence' => 'permanent',
+        'banking_enabled' => false,
+        'banking_auto_split_enabled' => false,
+        'banking_auto_split_savings_pct' => 0,
+        'banking_auto_split_charity_pct' => 0,
+        'banking_savings_monthly_interest_rate' => 0,
+        'banking_roundup_destination' => 'off',
         'timezone' => 'America/New_York',
         'week_starts_on' => 0,
         'calendar_two_way_google' => false,
@@ -80,6 +86,24 @@ function normalizeTimezoneToUs(string $tz, array $allowed): string {
 function normalizeLoadedFamilySettings(array $s): array {
     $allowed = familyHubUsTimezoneIdentifiers();
     $s['timezone'] = normalizeTimezoneToUs((string) ($s['timezone'] ?? ''), $allowed);
+    $bankingEnabled = $s['banking_enabled'] ?? false;
+    $s['banking_enabled'] = $bankingEnabled === true || $bankingEnabled === 1 || $bankingEnabled === '1' || $bankingEnabled === 'true';
+    $autoSplitEnabled = $s['banking_auto_split_enabled'] ?? false;
+    $s['banking_auto_split_enabled'] = $autoSplitEnabled === true || $autoSplitEnabled === 1 || $autoSplitEnabled === '1' || $autoSplitEnabled === 'true';
+    $savingsPct = (float) ($s['banking_auto_split_savings_pct'] ?? 0);
+    $charityPct = (float) ($s['banking_auto_split_charity_pct'] ?? 0);
+    $s['banking_auto_split_savings_pct'] = max(0, min(100, round($savingsPct, 2)));
+    $s['banking_auto_split_charity_pct'] = max(0, min(100, round($charityPct, 2)));
+    if (($s['banking_auto_split_savings_pct'] + $s['banking_auto_split_charity_pct']) > 100) {
+        $s['banking_auto_split_charity_pct'] = max(0, round(100 - $s['banking_auto_split_savings_pct'], 2));
+    }
+    $monthlyRate = (float) ($s['banking_savings_monthly_interest_rate'] ?? 0);
+    $s['banking_savings_monthly_interest_rate'] = max(0, round($monthlyRate, 6));
+    $roundupDestination = trim((string) ($s['banking_roundup_destination'] ?? 'off'));
+    if (!in_array($roundupDestination, ['off', 'savings', 'charity'], true)) {
+        $roundupDestination = 'off';
+    }
+    $s['banking_roundup_destination'] = $roundupDestination;
     $v = $s['calendar_two_way_google'] ?? false;
     $s['calendar_two_way_google'] = $v === true || $v === 1 || $v === '1' || $v === 'true';
     $s['calendar_bill_days'] = normalizeCalendarBillDaysRaw($s['calendar_bill_days'] ?? []);