fix: don't stretch the full-screen pull-down grabber across the whole width

A vertical LinearLayout defaults its children to MATCH_PARENT width, so the
collapsed grabber chip's rounded background spanned the entire screen. Give the
grabber explicit WRAP_CONTENT layout params (centered) so only the chip shows.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MgMpRcWj6y82LxLiwcuzmN

nappletHost/src/main/kotlin/com/vitorpamplona/amethyst/napplethost/NappletControlSheet.kt

@@ -222,6 +222,12 @@ class NappletControlSheet(
         return LinearLayout(context).apply {
             orientation = VERTICAL
             gravity = Gravity.CENTER_HORIZONTAL
+            // Wrap the grabber (a vertical LinearLayout defaults its children to MATCH_PARENT width, which
+            // would stretch this chip's background across the whole screen) and center it under the parent.
+            layoutParams =
+                LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT).apply {
+                    gravity = Gravity.CENTER_HORIZONTAL
+                }
             setPadding(dp(16), dp(7), dp(16), dp(7))
             background =
                 GradientDrawable().apply {