fix(mobile-native-chat): stop an unbounded send claiming an image turn already in the read

The image-preview pass runs before the rebase, so a send captured with no
boundary matched any image turn the settled read carried — binding the user's
freshly attached photo to an old one and retiring the bubble through
landedImagePendingIds, which short-circuits the retirement path entirely.
Pinning the tail in the rebase could not help: the claim was already made.
Such an entry now waits one tick and claims against a real tail.

mobile/src/session/use-mobile-native-chat-drafts-glued-pending.test.ts

@@ -25,6 +25,16 @@ function assistantTurn(id: string, text: string, timestamp: number): NativeChatM
   }
 }
 
+function imageTurn(id: string, path: string, timestamp: number): NativeChatMessage {
+  return {
+    id,
+    role: 'user',
+    blocks: [{ type: 'text', text: `[Image: source: ${path}]` }],
+    timestamp,
+    source: 'transcript'
+  }
+}
+
 /** Texts of the optimistic bubbles the chat list actually renders. */
 function renderedPendingTexts(
   messages: NativeChatMessage[],
@@ -299,6 +309,23 @@ describe('useMobileNativeChatDrafts glued pending sends', () => {
       expect(renderedPendingTexts(olderIdentical, state)).toEqual(['fix the', 'bug'])
     })
 
+    // The preview pass runs before the rebase, so an entry with no boundary
+    // would bind the user's fresh photo to whatever image turn the read carries.
+    it('does not bind a photo sent before the read to an image turn already in it', async () => {
+      await mount([], false, false)
+      act(() => {
+        const origin = state?.captureSendOrigin('')
+        if (origin) {
+          state?.acceptSend(origin, '', ['file:///new.png'])
+        }
+      })
+
+      const olderImage = [imageTurn('m1', '/old/photo.png', 1000)]
+      await update(olderImage)
+      expect(state?.imagePreviewsByMessageId).toEqual({})
+      expect(state?.pending.map((item) => item.images)).toEqual([['file:///new.png']])
+    })
+
     it('still retires them once their own glued row lands', async () => {
       await mount([], false, false)
       rapidSend('fix the', 'bug')

mobile/src/session/use-mobile-native-chat-drafts.ts

@@ -291,7 +291,13 @@ export function useMobileNativeChatDrafts(args: {
     if (pending.length === 0) {
       return
     }
-    const landedImagePreviews = findLandedImagePreviewEchoes(messages, pending)
+    // This pass runs before the rebase below, so a send captured with no
+    // boundary would claim any image turn in the read — binding the user's fresh
+    // photo to an old one. It waits a tick and claims against a real tail.
+    const landedImagePreviews = findLandedImagePreviewEchoes(
+      messages,
+      pending.filter((item) => item.baselineResolved)
+    )
     const landedImagePendingIds = new Set(landedImagePreviews.map((preview) => preview.pendingId))
     if (landedImagePreviews.length > 0) {
       setImagePreviewsBySession((previous) =>