fix(compose): Share-Button onPressIn fixes keyboard-tap, native iOS-Style

Diagnose: ComposeCard ist ListHeaderComponent der FlatList die
keyboardShouldPersistTaps="handled" hat. Aber das Prop propagiert nicht
rekursiv durch tiefere View-Ketten — der Share-Button-Pressable liegt
zu tief, der erste Tap dismissed nur die Tastatur.

Fix: onPress → onPressIn (fired beim Touch-Down vor Keyboard-Dismiss-
Logic). Identisch zum Pattern beim Bild-Icon. Guard if(!content.trim()
|| posting) repliziert die disabled-Logik die onPress hatte.

Style: native iOS Primary-Action-Button-Look:
- height 44→50, px-5→px-6
- rounded-full → borderRadius 12 (Rectangle statt Pill)
- Nunito_700Bold → 600SemiBold
- Plain text "Teilen", kein Icon

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/rebreak-native/components/ComposeCard.tsx

@@ -161,18 +161,20 @@ export function ComposeCard({ onPosted }: Props) {
               <Text className="text-sm text-neutral-400" style={{ fontFamily: 'Nunito_600SemiBold' }}>{t('common.cancel')}</Text>
             </Pressable>
             <Pressable
-              onPress={submit}
+              onPressIn={() => { if (!content.trim() || posting) return; submit(); }}
               disabled={!content.trim() || posting}
-              className="px-5 rounded-full bg-rebreak-500 items-center justify-center"
+              className="bg-rebreak-500 items-center justify-center"
               style={({ pressed }) => ({
-                height: 44,
+                height: 50,
+                paddingHorizontal: 24,
+                borderRadius: 12,
                 opacity: pressed || !content.trim() || posting ? 0.5 : 1,
               })}
             >
               {posting ? (
                 <ActivityIndicator size="small" color="#fff" />
               ) : (
-                <Text className="text-white text-base" style={{ fontFamily: 'Nunito_700Bold' }}>{t('community.share')}</Text>
+                <Text className="text-white text-base" style={{ fontFamily: 'Nunito_600SemiBold' }}>{t('community.share')}</Text>
               )}
             </Pressable>
           </View>