feat: 国际化(i18n) en/ja/ko + App 内语言切换

主体:多语言支持(简体中文源 + 英/日/韩)
- 基础设施:Localizable.xcstrings(String Catalog,sourceLanguage=zh-Hans)
  + pbxproj developmentRegion/knownRegions 注册 en/ja/ko
- 全部硬编码 Locale("zh_CN") → Locale.current;中文 dateFormat → Date.FormatStyle(跟随系统)
- UI 中文字面量统一为 String(appLoc:)(显式绑定所选语言 bundle+locale,即时切换)
  Text 字面量走环境 \.locale + Bundle 重定向
- 549 个 catalog key 全部 en/ja/ko 翻译完成(0 未翻译)
- App 内语言切换:我的 → 语言(LanguageManager + 即时生效,无需重启)
- 双用预设(症状/监测指标/慢病)本地化:static→computed 避免缓存

注:本提交为 WIP,一并打包了并行进行的功能模块
(HealthExport 健康导出、Security/Face ID 锁、DiaryAssist 日记 AI 辅助)
及 App 图标、CLAUDE.md、docs/scripts。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

康康/Features/Trends/CalendarMonthGrid.swift

@@ -3,16 +3,31 @@ import SwiftUI
 struct CalendarMonthGrid: View {
     let monthAnchor: Date
     let data: CalendarData
+    let selectedDate: Date?
     let onTapDay: (Date) -> Void
 
+    init(monthAnchor: Date,
+         data: CalendarData,
+         selectedDate: Date? = nil,
+         onTapDay: @escaping (Date) -> Void) {
+        self.monthAnchor = monthAnchor
+        self.data = data
+        self.selectedDate = selectedDate
+        self.onTapDay = onTapDay
+    }
+
     private let calendar: Calendar = {
         var c = Calendar(identifier: .gregorian)
         c.firstWeekday = 2 // 周一开始
-        c.locale = Locale(identifier: "zh_CN")
+        c.locale = Locale.current
         return c
     }()
 
-    private let weekdayLabels = ["一", "二", "三", "四", "五", "六", "日"]
+    private let weekdayLabels = [
+        String(appLoc: "一"), String(appLoc: "二"), String(appLoc: "三"),
+        String(appLoc: "四"), String(appLoc: "五"), String(appLoc: "六"),
+        String(appLoc: "日")
+    ]
     private let columns = Array(repeating: GridItem(.flexible(), spacing: 4), count: 7)
 
     private var days: [DayCell] {
@@ -64,6 +79,9 @@ struct CalendarMonthGrid: View {
                         ranges: data.ranges(touching: cell.date, calendar: calendar),
                         marks: data.marks(for: cell.date, calendar: calendar),
                         isToday: calendar.isDateInToday(cell.date),
+                        isSelected: selectedDate.map {
+                            calendar.isDate(cell.date, inSameDayAs: $0)
+                        } ?? false,
                         calendar: calendar
                     )
                     .onTapGesture { onTapDay(cell.date) }
@@ -84,6 +102,7 @@ private struct DayCellView: View {
     let ranges: [SymptomRange]
     let marks: DayMarks
     let isToday: Bool
+    let isSelected: Bool
     let calendar: Calendar
 
     private var dayNumber: Int {
@@ -92,14 +111,20 @@ private struct DayCellView: View {
 
     var body: some View {
         ZStack(alignment: .top) {
-            // 背景:今天高亮
+            // 背景层:selected > today
             RoundedRectangle(cornerRadius: 6, style: .continuous)
-                .fill(isToday ? Tj.Palette.sand2 : Color.clear)
+                .fill(backgroundFill)
+
+            // 选中描边
+            if isSelected {
+                RoundedRectangle(cornerRadius: 6, style: .continuous)
+                    .strokeBorder(Tj.Palette.brick, lineWidth: 1.5)
+            }
 
             VStack(spacing: 2) {
                 Text("\(dayNumber)")
                     .font(.system(size: 13,
-                                  weight: isToday ? .bold : .regular,
+                                  weight: (isToday || isSelected) ? .bold : .regular,
                                   design: .default))
                     .foregroundStyle(textColor)
                     .padding(.top, 4)
@@ -145,10 +170,17 @@ private struct DayCellView: View {
 
     private var textColor: Color {
         if !cell.inCurrentMonth { return Tj.Palette.text3.opacity(0.5) }
+        if isSelected { return Tj.Palette.brick }
         if isToday { return Tj.Palette.ink }
         return Tj.Palette.text
     }
 
+    private var backgroundFill: Color {
+        if isSelected { return Tj.Palette.brickSoft.opacity(0.5) }
+        if isToday { return Tj.Palette.sand2 }
+        return .clear
+    }
+
     private func symptomBar(_ range: SymptomRange) -> some View {
         let pos = range.position(cell.date, calendar: calendar)
         let leadingRadius: CGFloat = (pos == .start || pos == .single) ? 3 : 0