feat: add long-press contextual actions on post cards

Long press any post card to open a context menu with state-aware actions:
- Copy text (all states)
- ERROR: Retry now, Edit & retry, View error message
- QUEUE: Edit, Reschedule (native DateTimePicker → PUT /posts/:id)
- PUBLISHED: Repost
- DRAFT: Edit & schedule

Compose screen now accepts prefillContent/prefillIntegrationIds router
params to pre-fill content and channel selection when editing or reposting.
Adds expo-clipboard for clipboard support.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

artifacts/postiz-mobile/components/PostCard.tsx

@@ -17,6 +17,7 @@ import { StatusBadge } from "./StatusBadge";
 interface PostCardProps {
   post: PostizPost;
   onDelete: (id: string) => Promise<void>;
+  onLongPress: (post: PostizPost) => void;
 }
 
 function formatDate(dateStr: string): string {
@@ -43,7 +44,7 @@ function getNetworkIcon(type?: string): React.ComponentProps<typeof Feather>["na
   return "globe";
 }
 
-export function PostCard({ post, onDelete }: PostCardProps) {
+export function PostCard({ post, onDelete, onLongPress }: PostCardProps) {
   const colors = useColors();
   const swipeRef = useRef<Swipeable>(null);
 
@@ -100,7 +101,10 @@ export function PostCard({ post, onDelete }: PostCardProps) {
       rightThreshold={40}
       friction={2}
     >
-      <View
+      <TouchableOpacity
+        activeOpacity={0.85}
+        onLongPress={() => onLongPress(post)}
+        delayLongPress={400}
         style={[
           styles.card,
           { backgroundColor: colors.card, borderBottomColor: colors.border },
@@ -140,7 +144,7 @@ export function PostCard({ post, onDelete }: PostCardProps) {
             {formatDate(post.publishDate)}
           </Text>
         </View>
-      </View>
+      </TouchableOpacity>
     </Swipeable>
   );
 }