feat: macOS architecture, cloud ASR/LLM providers, and 6-step iOS onboarding

- Add macOS menu-bar dictation app with local ASR models (SenseVoice/Qwen3),
  global Option hotkey, and bottom overlay
- Add cloud ASR/LLM providers (Anthropic, Volcengine, Bailian, and more) with
  provider logos, model listing, and connection checks
- Add shared 7-day usage stats UI (UsageStatsCluster / SevenDayUsageChart)
- Add iOS onboarding step 6 for polish LLM setup; hide custom-language-model
  diagnostic toggle behind DEBUG
- Unify iOS onboarding tagline with the macOS brand line ("开口即文字。")
- Rewrite README (Chinese-first, product-oriented) and refresh GitHub Pages

OSGKeyboardShared/DesignSystem/Theme.swift

@@ -162,10 +162,13 @@ public enum Radius {
 // MARK: - Typography
 
 public enum SettingsListMetrics {
-    /// Single-line list rows (provider, footer link, picker).
-    public static let singleLineMinHeight: CGFloat = 52
-    /// Two-line rows (engine option, labeled API field).
-    public static let doubleLineMinHeight: CGFloat = 72
+    /// Floor for settings list rows (slightly above HIG 44pt).
+    /// Row height grows with content; this only enforces a touch-target minimum.
+    public static let singleLineMinHeight: CGFloat = 48
+    /// Horizontal inset inside a settings list row.
+    public static let rowHorizontalPadding: CGFloat = Spacing.md
+    /// Vertical inset inside a settings list row (`Spacing.sm`).
+    public static let rowVerticalPadding: CGFloat = 12
     /// Space between a section label and its card.
     public static let sectionLabelSpacing: CGFloat = Spacing.sm
 }
@@ -263,6 +266,19 @@ private struct SecondaryButtonModifier: ViewModifier {
 }
 
 public extension View {
+    /// Standard settings list row insets: horizontal + vertical padding and a
+    /// touch-target floor. Height grows with content — do not hand-roll
+    /// per-section padding/`minHeight` for ordinary settings rows.
+    func settingsListRow(
+        minHeight: CGFloat = SettingsListMetrics.singleLineMinHeight,
+        alignment: Alignment = .center
+    ) -> some View {
+        self
+            .padding(.horizontal, SettingsListMetrics.rowHorizontalPadding)
+            .padding(.vertical, SettingsListMetrics.rowVerticalPadding)
+            .frame(minHeight: minHeight, alignment: alignment)
+    }
+
     /// Standard card surface used in the main app.
     func cardSurface(padding: CGFloat = Spacing.md) -> some View {
         modifier(CardSurfaceModifier(padding: padding))