v1.2.1: Add sort settings (change% asc/desc, US session/regular price mode)

- Add SortRule enum (涨跌幅升序/降序) and USPriceMode enum (时段价格/盘中价)
- Settings page: sort rule segmented picker + US price mode picker
- Toolbar sort button applies configured rule; off = default order
- US stocks: session price mode uses extendedPrice for change% calculation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

StockMonitor/Models/AppSettings.swift

@@ -22,6 +22,30 @@ enum DisplayCurrency: String, Codable, CaseIterable {
     }
 }
 
+enum SortRule: String, Codable, CaseIterable {
+    case changeDesc = "changeDesc"
+    case changeAsc  = "changeAsc"
+
+    var displayName: String {
+        switch self {
+        case .changeDesc: return "涨跌幅降序"
+        case .changeAsc:  return "涨跌幅升序"
+        }
+    }
+}
+
+enum USPriceMode: String, Codable, CaseIterable {
+    case sessionPrice = "session"
+    case regularPrice = "regular"
+
+    var displayName: String {
+        switch self {
+        case .sessionPrice: return "当前价（时段价格）"
+        case .regularPrice: return "盘中价"
+        }
+    }
+}
+
 enum ColorTheme: String, Codable, CaseIterable {
     case chinese = "chinese"  // 红涨绿跌
     case western = "western"  // 绿涨红跌
@@ -39,6 +63,8 @@ struct AppSettings {
     var refreshInterval: Int             = 5
     var colorScheme: ColorTheme          = .chinese
     var displayCurrency: DisplayCurrency = .cny
+    var sortRule: SortRule               = .changeDesc
+    var usPriceMode: USPriceMode         = .sessionPrice
 
     static let validRefreshIntervals = [3, 5, 10, 30]
 
@@ -49,7 +75,7 @@ struct AppSettings {
 // MARK: - Codable（容错：缺失字段使用默认值）
 extension AppSettings: Codable {
     enum CodingKeys: String, CodingKey {
-        case statusBarStockId, refreshInterval, colorScheme, displayCurrency
+        case statusBarStockId, refreshInterval, colorScheme, displayCurrency, sortRule, usPriceMode
     }
 
     init(from decoder: Decoder) throws {
@@ -58,5 +84,7 @@ extension AppSettings: Codable {
         refreshInterval  = (try? c.decodeIfPresent(Int.self,             forKey: .refreshInterval))   ?? 5
         colorScheme      = (try? c.decodeIfPresent(ColorTheme.self,      forKey: .colorScheme))       ?? .chinese
         displayCurrency  = (try? c.decodeIfPresent(DisplayCurrency.self, forKey: .displayCurrency))   ?? .cny
+        sortRule         = (try? c.decodeIfPresent(SortRule.self,         forKey: .sortRule))           ?? .changeDesc
+        usPriceMode      = (try? c.decodeIfPresent(USPriceMode.self,     forKey: .usPriceMode))        ?? .sessionPrice
     }
 }

StockMonitor/Views/DropdownView.swift

@@ -10,16 +10,29 @@ struct DropdownView: View {
         [Market.aStock, .hkStock, .usStock].compactMap { market in
             var s = appState.stocks.filter { $0.market == market }
             if sortByChange {
-                s.sort {
-                    let a = appState.quotes[$0.id]?.changePercent ?? -Double.infinity
-                    let b = appState.quotes[$1.id]?.changePercent ?? -Double.infinity
-                    return a > b
+                let rule = appState.config.sortRule
+                let usMode = appState.config.usPriceMode
+                s.sort { a, b in
+                    let qa = appState.quotes[a.id]
+                    let qb = appState.quotes[b.id]
+                    let va = sortValue(quote: qa, market: market, mode: usMode)
+                    let vb = sortValue(quote: qb, market: market, mode: usMode)
+                    return rule == .changeDesc ? va > vb : va < vb
                 }
             }
             return s.isEmpty ? nil : (market, s)
         }
     }
 
+    private func sortValue(quote: Quote?, market: Market, mode: USPriceMode) -> Double {
+        guard let q = quote else { return -Double.infinity }
+        if market == .usStock && mode == .sessionPrice, let ext = q.extendedPrice {
+            // 用时段价格算涨跌幅：(盘外价 - 正盘价) / 正盘价
+            return q.price > 0 ? (ext - q.price) / q.price * 100 : q.changePercent
+        }
+        return q.changePercent
+    }
+
     var body: some View {
         VStack(alignment: .leading, spacing: 4) {
             if showSettings {

StockMonitor/Views/SettingsView.swift

@@ -54,6 +54,30 @@ struct SettingsView: View {
                     }.pickerStyle(.menu)
                 }
 
+                // 排序规则
+                section("排序规则") {
+                    Picker("", selection: Binding(
+                        get: { appState.config.sortRule },
+                        set: { appState.config.sortRule = $0 }
+                    )) {
+                        ForEach(SortRule.allCases, id: \.rawValue) { rule in
+                            Text(rule.displayName).tag(rule)
+                        }
+                    }.pickerStyle(.segmented)
+                }
+
+                // 美股排序价格
+                section("美股排序价格") {
+                    Picker("", selection: Binding(
+                        get: { appState.config.usPriceMode },
+                        set: { appState.config.usPriceMode = $0 }
+                    )) {
+                        ForEach(USPriceMode.allCases, id: \.rawValue) { mode in
+                            Text(mode.displayName).tag(mode)
+                        }
+                    }.pickerStyle(.segmented)
+                }
+
                 // 刷新间隔
                 section("刷新间隔") {
                     Picker("", selection: Binding(