Reject decimal input in the manual "currency to Sats" field

It was using the decimal sanitizer/keyboard, same as the rate field
next to it — but Sats are indivisible, so this one should behave like
the existing Sats amount field: integers only, numeric keypad.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FXcrACM5sok3M1KQJ8kByy

iosApp/iosApp/ContentView.swift

@@ -115,8 +115,8 @@ struct ContentView: View {
                         NumericField(
                             placeholder: "",
                             value: state.manualSatsPerCurrencyInput,
-                            keyboardType: .decimalPad,
-                            sanitize: sanitizeDecimalInput,
+                            keyboardType: .numberPad,
+                            sanitize: sanitizeIntegerInput,
                             onChange: { viewModel.onManualSatsPerCurrencyChanged($0) },
                             alignment: .trailing
                         )

shared/src/commonMain/kotlin/xyz/tyiu/satsprice/ui/PriceScreen.kt

@@ -214,7 +214,7 @@ fun PriceScreen(
                             value = state.manualSatsPerCurrencyInput,
                             onValueChange = viewModel::onManualSatsPerCurrencyChanged,
                             label = { Text(stringResource(MR.strings.currency_to_sats, state.defaultCurrencyCode)) },
-                            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Decimal),
+                            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
                             singleLine = true,
                             visualTransformation = DigitGroupingTransformation,
                             modifier = Modifier.fillMaxWidth(),

shared/src/commonMain/kotlin/xyz/tyiu/satsprice/ui/PriceViewModel.kt

@@ -294,7 +294,8 @@ class PriceViewModel(
     }
 
     fun onManualSatsPerCurrencyChanged(value: String) {
-        val sanitized = sanitizeDecimalInput(value)
+        // Sats are indivisible — unlike the rate field, this one takes whole numbers only.
+        val sanitized = sanitizeIntegerInput(value)
         val parsedSats = sanitized.toBigDecimalOrNull()
         val rate = parsedSats?.let { sats -> CurrencyConverter.satsPerCurrencyUnit(sats) }
         manualSource.rate = rate