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

OSGKeyboardLiveActivity/FlowLiveActivityWidget.swift

@@ -66,7 +66,7 @@ private struct FlowLiveActivityLockScreenView: View {
 
     var body: some View {
         HStack(spacing: 12) {
-            FlowLiveActivityBrandMark(height: 13)
+            FlowLiveActivityBrandMark(height: 10.4)
             VStack(alignment: .leading, spacing: 4) {
                 Text("OSGKeyboard")
                     .font(.headline)