feat: round raid and clip stream cards to match the chat design

StreamSystemCard's default corner shape moves from 8dp to 18dp so the
full-width raid and clip cards share the rounding of the redesigned
bubbles, zap pills, and system messages. The zap renderer drops its now
redundant shape override.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0129yvP2hmVeDFfuKKy94tqX

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/feed/types/RenderChatZap.kt

@@ -25,7 +25,6 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
@@ -56,9 +55,6 @@ import com.vitorpamplona.quartz.nip57Zaps.LnZapEvent
 
 private const val BIG_ZAP_THRESHOLD_SATS = 50_000L
 
-// Matches the 18dp rounding of the redesigned chat bubbles / system pills.
-private val ChatZapCardShape = RoundedCornerShape(18.dp)
-
 @Composable
 fun RenderChatZap(
     baseNote: Note,
@@ -88,7 +84,6 @@ fun RenderChatZap(
         accent = BitcoinOrange,
         accentAlpha = accentAlpha,
         fillWidth = false,
-        shape = ChatZapCardShape,
     ) {
         val backgroundColor = remember(accentAlpha) { mutableStateOf(BitcoinOrange.copy(alpha = accentAlpha)) }
 

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/nip53LiveActivities/ui/StreamSystemCard.kt

@@ -53,7 +53,8 @@ fun StreamSystemCard(
     accentAlpha: Float = 0.12f,
     onClick: (() -> Unit)? = null,
     fillWidth: Boolean = true,
-    shape: Shape = RoundedCornerShape(8.dp),
+    // 18dp matches the rounding of the redesigned chat bubbles and system pills.
+    shape: Shape = RoundedCornerShape(18.dp),
     content: @Composable BoxScope.() -> Unit,
 ) {
     val base =