fix(mobile): stop alerting that shared content vanished after sending it

Since #10435, sending a new task clears the composer draft synchronously
but defers the navigation by a frame. The share import effect re-ran in
that frame: the draft's importedShareIds receipt was gone, the inbox entry
had already been consumed, so the share looked unavailable and the screen
raised "Shared content unavailable" over a task that had just sent fine.

Remember the share this screen consumed and treat it as imported for the
rest of the screen's life, independent of the draft's receipt.

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

Author: juliusmarminge

apps/mobile/src/features/threads/NewTaskDraftScreen.tsx

@@ -323,6 +323,11 @@ export function NewTaskDraftScreen(props: {
   latestIncomingShareIdRef.current = props.incomingShareId;
   const isImportingShare = importingShareKey !== null;
   const alertedUnavailableIncomingShareIdRef = useRef<string | null>(null);
+  // The share this screen already moved into its draft. Sending clears the
+  // draft (and its importedShareIds receipt) a frame before the screen leaves,
+  // and the inbox entry is long gone by then; without this the re-render in
+  // between reads as "shared content vanished" and alerts on every send.
+  const consumedIncomingShareIdRef = useRef<string | null>(null);
   const incomingShare = props.incomingShareId ? getShare(props.incomingShareId) : null;
   const requestedInitialProjectAvailable = Boolean(
     props.initialProjectRef?.environmentId &&
@@ -416,8 +421,9 @@ export function NewTaskDraftScreen(props: {
   }, [navigation, preventRemove, submitNavigationAction]);
   const hasImportedIncomingShare = Boolean(
     props.incomingShareId &&
-    flow.draftKey &&
-    getComposerDraftSnapshot(flow.draftKey).importedShareIds?.includes(props.incomingShareId),
+    (consumedIncomingShareIdRef.current === props.incomingShareId ||
+      (flow.draftKey &&
+        getComposerDraftSnapshot(flow.draftKey).importedShareIds?.includes(props.incomingShareId))),
   );
   const isIncomingShareUnavailable = Boolean(
     props.incomingShareId &&
@@ -747,6 +753,7 @@ export function NewTaskDraftScreen(props: {
       }
       await consumeShare(shareId);
       didConsumeShare = true;
+      consumedIncomingShareIdRef.current = shareId;
       // The consumed inbox draft was the last owner of files that never made
       // it into the composer draft (unsupported server, oversize, limit
       // skips). Release them before any early return: an unmount or a