refactor(commons): extract activity-card building blocks to commons

Seventh batch of the note-ui-commons extraction. The activity-card slot
composables — the gradient frame, kind badge, header row, amount row, and
pill shared by the reaction / zap / nutzap renderings — are pure
value/slot-in with no strings, so they move as-is.

- commons/ui/note/ActivityCard.kt: ActivityCardFrame, ActivityBadge,
  ActivityPill, ActivityHeaderRow, ActivityAmountRow, and the LikeTint color.
- commons/ui/theme/Sizes.kt: shared Size16Modifier (and Size5dp for the next
  batch), mirroring the Android ui/theme values.
- Consumers (Reaction, ZapEvent, Nutzap) re-point their imports to commons.

Verified: :commons:compileKotlinJvm and :amethyst:compileFdroidDebugKotlin
both pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gmrt3jwYPDJ38MJGJ6GaNr

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/Nutzap.kt

@@ -30,6 +30,10 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.dp
 import com.vitorpamplona.amethyst.commons.hashtags.Cashu
 import com.vitorpamplona.amethyst.commons.hashtags.CustomHashTagIcons
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityAmountRow
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityBadge
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityCardFrame
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityHeaderRow
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.note.CrossfadeToDisplayComment

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/Reaction.kt

@@ -26,6 +26,10 @@ import androidx.compose.runtime.MutableState
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityBadge
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityCardFrame
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityHeaderRow
+import com.vitorpamplona.amethyst.commons.ui.note.LikeTint
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.note.DisplayBlankAuthor

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/ZapEvent.kt

@@ -40,6 +40,10 @@ import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
 import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityAmountRow
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityBadge
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityCardFrame
+import com.vitorpamplona.amethyst.commons.ui.note.ActivityHeaderRow
 import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.User

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/note/ActivityCard.kt

@@ -18,7 +18,7 @@
  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
-package com.vitorpamplona.amethyst.ui.note.types
+package com.vitorpamplona.amethyst.commons.ui.note
 
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
@@ -48,7 +48,7 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
 import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
-import com.vitorpamplona.amethyst.ui.theme.Size16Modifier
+import com.vitorpamplona.amethyst.commons.ui.theme.Size16Modifier
 
 /**
  * Heart color of the Liked icon vector; tints reaction activity cards the way

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/theme/Sizes.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.ui.theme
+
+import androidx.compose.foundation.layout.size
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+
+// Fixed-size icon modifiers shared by the event-kind renderers pulled down from
+// the Android app. Mirror the values in the app's ui/theme/Shape.kt; the Android
+// copies become dead code as each renderer moves and are deleted at the end.
+
+/** 5dp fixed size. */
+val Size5dp = 5.dp
+
+/** 16dp square icon modifier. */
+val Size16Modifier = Modifier.size(16.dp)