feat(mobile): ReactionStrip quick-reactor + ReactionPills display

apps/mobile/components/ReactionPills.tsx

@@ -0,0 +1,67 @@
+import type { MessageReaction } from '@chat-app/shared/chat';
+import { useMemo } from 'react';
+import { Pressable, StyleSheet, Text, View } from 'react-native';
+
+import { colors } from '../theme/colors';
+
+interface Props {
+  reactions: MessageReaction[];
+  myUserId: string | null;
+  onToggle: (emoji: string) => void;
+}
+
+// Renders the per-message reaction badges underneath a bubble. Pills
+// the current user has reacted to get a tinted background so they know
+// which ones to tap to un-react.
+export function ReactionPills({ reactions, myUserId, onToggle }: Props) {
+  const grouped = useMemo(() => groupByEmoji(reactions, myUserId), [reactions, myUserId]);
+  if (grouped.length === 0) return null;
+  return (
+    <View style={styles.row}>
+      {grouped.map((g) => (
+        <Pressable
+          key={g.emoji}
+          onPress={() => onToggle(g.emoji)}
+          style={[styles.pill, g.mine && styles.pillMine]}
+        >
+          <Text style={styles.emoji}>{g.emoji}</Text>
+          <Text style={[styles.count, g.mine && styles.countMine]}>{g.count}</Text>
+        </Pressable>
+      ))}
+    </View>
+  );
+}
+
+function groupByEmoji(
+  rows: MessageReaction[],
+  myUserId: string | null,
+): Array<{ emoji: string; count: number; mine: boolean }> {
+  const m = new Map<string, { count: number; mine: boolean }>();
+  for (const r of rows) {
+    const prev = m.get(r.emoji) ?? { count: 0, mine: false };
+    m.set(r.emoji, {
+      count: prev.count + 1,
+      mine: prev.mine || (myUserId !== null && r.userId === myUserId),
+    });
+  }
+  return Array.from(m.entries()).map(([emoji, v]) => ({ emoji, ...v }));
+}
+
+const styles = StyleSheet.create({
+  row: { flexDirection: 'row', flexWrap: 'wrap', gap: 4, marginTop: 4 },
+  pill: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    paddingHorizontal: 8,
+    paddingVertical: 2,
+    borderRadius: 12,
+    backgroundColor: colors.surface,
+    borderColor: colors.border,
+    borderWidth: 1,
+    gap: 4,
+  },
+  pillMine: { backgroundColor: colors.accentMuted, borderColor: colors.accent },
+  emoji: { fontSize: 13 },
+  count: { color: colors.textMuted, fontSize: 12, fontWeight: '600' },
+  countMine: { color: colors.accent },
+});

apps/mobile/components/ReactionStrip.tsx

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+import { Pressable, StyleSheet, Text, View } from 'react-native';
+
+import { colors } from '../theme/colors';
+
+// Hardcoded 6-emoji quick reactor shown at the top of the long-press
+// sheet. A full emoji picker is post-Phase-4; this is the Discord-style
+// fast path the vast majority of reactions go through.
+export const QUICK_REACTIONS = ['👍', '❤️', '😂', '😮', '😢', '🎉'] as const;
+
+export function ReactionStrip({ onReact }: { onReact: (emoji: string) => void }) {
+  return (
+    <View style={styles.row}>
+      {QUICK_REACTIONS.map((e) => (
+        <Pressable
+          key={e}
+          onPress={() => onReact(e)}
+          style={({ pressed }) => [styles.button, pressed && styles.buttonPressed]}
+          hitSlop={6}
+        >
+          <Text style={styles.emoji}>{e}</Text>
+        </Pressable>
+      ))}
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  row: {
+    flexDirection: 'row',
+    justifyContent: 'space-around',
+    paddingVertical: 12,
+    paddingHorizontal: 8,
+    borderBottomColor: colors.border,
+    borderBottomWidth: 1,
+  },
+  button: {
+    width: 44,
+    height: 44,
+    alignItems: 'center',
+    justifyContent: 'center',
+    borderRadius: 22,
+  },
+  buttonPressed: { backgroundColor: colors.accentMuted },
+  emoji: { fontSize: 26 },
+});