Always show all currencies, flagging ones the active source doesn't price

Previously a currency the active price source had no rate for was hidden
entirely, so switching sources (e.g. to CoinGecko, which quotes far fewer
fiat currencies than Coinbase) could silently drop it from the picker and
even from the user's own selection.

Every system currency is now always offered. ConverterUiState tracks which
codes the latest fetch actually priced, and both UIs (Compose and the
native SwiftUI screen, since iOS/macOS don't render Compose UI at all) show
a "Not priced by <source>" indicator for the rest, with the amount field
emptied and disabled rather than showing a stale or meaningless value.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QpjMKWGoiT5aJBzhxvXkwp

iosApp/iosApp/ContentView.swift

@@ -129,6 +129,8 @@ struct ContentView: View {
                         keyboardType: .decimalPad,
                         sanitize: sanitizeDecimalInput,
                         onChange: { viewModel.onFiatAmountChanged(code: row.code, value: $0) },
+                        isPriced: state.pricedCurrencyCodes.contains(row.code),
+                        sourceName: state.sourceName,
                         onMoveUp: index > 0 ? {
                             var codes = state.fiatRows.map(\.code)
                             codes.move(fromOffsets: [index], toOffset: index - 1)
@@ -164,6 +166,8 @@ struct ContentView: View {
                 currentCurrency: state.currentCurrency,
                 selectedOtherCurrencies: state.selectedOtherCurrencies,
                 unselectedCurrencies: state.unselectedCurrencies,
+                pricedCurrencyCodes: state.pricedCurrencyCodes,
+                sourceName: state.sourceName,
                 localeCurrencyCode: state.localeCurrencyCode,
                 onToggle: { viewModel.onFiatCurrencyToggled($0) }
             )
@@ -202,6 +206,8 @@ struct ContentView: View {
         keyboardType: NumericFieldKeyboard,
         sanitize: @escaping (String) -> String,
         onChange: @escaping (String) -> Void,
+        isPriced: Bool = true,
+        sourceName: String = "",
         onMoveUp: (() -> Void)? = nil,
         onMoveDown: (() -> Void)? = nil
     ) -> some View {
@@ -226,16 +232,27 @@ struct ContentView: View {
                 .buttonStyle(.borderless)
             }
             #endif
-            Text(label)
+            VStack(alignment: .leading) {
+                Text(label)
+                if !isPriced {
+                    Text(IosLocalizationKt.localizedFormattedString(
+                        resource: MR.strings.shared.currency_not_priced,
+                        args: [sourceName]
+                    ))
+                    .font(.caption2)
+                    .foregroundColor(.red)
+                }
+            }
             Spacer()
             NumericField(
                 placeholder: "",
-                value: value,
+                value: isPriced ? value : "",
                 keyboardType: keyboardType,
                 sanitize: sanitize,
                 onChange: onChange,
                 alignment: .trailing
             )
+            .disabled(!isPriced)
         }
     }
 }

iosApp/iosApp/CurrencyPickerSheet.swift

@@ -5,6 +5,8 @@ struct CurrencyPickerSheet: View {
     let currentCurrency: CurrencyInfo
     let selectedOtherCurrencies: [CurrencyInfo]
     let unselectedCurrencies: [CurrencyInfo]
+    let pricedCurrencyCodes: [String]
+    let sourceName: String
     let localeCurrencyCode: String?
     let onToggle: (String) -> Void
 
@@ -51,9 +53,20 @@ struct CurrencyPickerSheet: View {
 
     @ViewBuilder
     private func currencyRow(for info: CurrencyInfo, isSelected: Bool, onTap: (() -> Void)?) -> some View {
+        let isPriced = pricedCurrencyCodes.contains(info.code)
         let content = HStack {
-            Text(currencyLabel(for: info))
-                .foregroundColor(.primary)
+            VStack(alignment: .leading) {
+                Text(currencyLabel(for: info))
+                    .foregroundColor(.primary)
+                if !isPriced {
+                    Text(IosLocalizationKt.localizedFormattedString(
+                        resource: MR.strings.shared.currency_not_priced,
+                        args: [sourceName]
+                    ))
+                    .font(.caption)
+                    .foregroundColor(.red)
+                }
+            }
             Spacer()
             if isSelected {
                 Image(systemName: "checkmark")