feat(keyboard): ship AI hint carousel, home library cards, and clipboard polish

Rotate AI idle suggestions with optional remote packs, move history/dictionary onto self-sizing Home preview cards, harden clipboard capture/prompting, and simplify keyboard chrome by dropping most liquid-glass shadows.

OSGKeyboardExt/Typing/TypingRootView.swift

@@ -122,7 +122,9 @@ struct TypingRootView: View {
         if hasCandidateContent {
             // Composing Chinese/English candidates hide the clipboard strip.
             candidateBar
-        } else if let suggestion = state.clipboardSuggestionText, !suggestion.isEmpty {
+        } else if state.canShowClipboardEntry,
+                  let suggestion = state.clipboardSuggestionText,
+                  !suggestion.isEmpty {
             // Same slot as logo + capsule tabs — hide chrome until dismissed.
             ClipboardSuggestionBar(
                 text: suggestion,
@@ -548,6 +550,7 @@ struct TypingRootView: View {
             )
             .fill(visualKeyFill(for: key, pressed: showPressed))
         )
+        // 无投影：与 NativeKeyboardKeySurface 一致，靠填充 + 描边表达层次。
         .overlay(
             RoundedRectangle(
                 cornerRadius: TypingLayoutMetrics.keyCornerRadius,
@@ -555,11 +558,6 @@ struct TypingRootView: View {
             )
             .stroke(visualKeyBorder(for: key), lineWidth: 0.5)
         )
-        .shadow(
-            color: Color.black.opacity(showPressed ? 0.04 : 0.13),
-            radius: showPressed ? 0.5 : 1,
-            y: showPressed ? 0 : 1
-        )
         .scaleEffect(pressed ? 0.98 : 1)
         .animation(.easeOut(duration: 0.08), value: pressed)
         .accessibilityElement()