refactor(mothership): a saved Stop handoff's id wins on restore

When an entry saved with an id on its Stop handoff also has its own
resumeUserMessageId, the handoff's id is the one that build sent, so it
is the one kept. resumeUserMessageId's doc names every path that sets it.

Author: waleedlatif1

apps/sim/stores/mothership-queue/store.dom.test.ts

@@ -77,7 +77,7 @@ describe('useMothershipQueueStore rehydration', () => {
     expect(plain?.admissionUnknown).toBeUndefined()
   })
 
-  it('moves the reused id a saved Stop handoff carried onto the entry', async () => {
+  it('moves the reused id a saved Stop handoff carried onto the entry, over its own', async () => {
     const seed = { chatId: 'chat-A', supersededStreamId: 'previous-response', stopRequired: true }
     sessionStorage.setItem(
       'mothership-queue',
@@ -96,6 +96,12 @@ describe('useMothershipQueueStore rehydration', () => {
                 admissionUnknown: false,
                 queuedSendHandoff: { id: 'never-sent', ...seed, userMessageId: 'attempt-2' },
               },
+              {
+                id: 'both',
+                content: 'c',
+                resumeUserMessageId: 'withdrawn-attempt',
+                queuedSendHandoff: { id: 'both', ...seed, userMessageId: 'send-now-attempt' },
+              },
             ],
           },
         },
@@ -120,6 +126,14 @@ describe('useMothershipQueueStore rehydration', () => {
         admissionUnknown: false,
         queuedSendHandoff: { id: 'never-sent', ...seed },
       },
+      {
+        id: 'both',
+        content: 'c',
+        /** The id that build sent: the handoff's, ahead of the entry's. */
+        resumeUserMessageId: 'send-now-attempt',
+        admissionUnknown: true,
+        queuedSendHandoff: { id: 'both', ...seed },
+      },
     ])
   })
 })

apps/sim/stores/mothership-queue/store.ts

@@ -85,12 +85,13 @@ function withCurrentWaitFields(value: unknown): unknown {
   if (!record) return value
   const { retryRequired, heldUntilOnline, sendRetries, notBefore, ...rest } = record
   /* An entry saved when its Stop handoff carried the reused id: that id is the
-     entry's `resumeUserMessageId` now. */
+     entry's `resumeUserMessageId` now. It wins over the entry's own, as it did
+     when that build picked the id to send. */
   const seed = toRecordOrNull(rest.queuedSendHandoff)
   if (seed && typeof seed.userMessageId === 'string') {
     const { userMessageId: seedRequestId, ...seedRest } = seed
     rest.queuedSendHandoff = seedRest
-    if (rest.resumeUserMessageId === undefined) rest.resumeUserMessageId = seedRequestId
+    rest.resumeUserMessageId = seedRequestId
   }
   return {
     ...rest,

apps/sim/stores/mothership-queue/types.ts

@@ -34,11 +34,13 @@ export type QueuedMothershipMessage = QueuedMessage & {
    */
   retry?: SendRetry
   /**
-   * Message id of a prior attempt at this send that an unmount cleanup
-   * withdrew. Reused when the entry is dispatched so the server deduplicates
-   * against that attempt — it never sees the client's abort, so a request it
-   * had already accepted still opened the chat and billed the turn. Persisted,
-   * so a retry after a reload deduplicates too.
+   * Message id of an earlier attempt at this send, the one id it goes out
+   * under: a send an unmount cleanup withdrew, a Send-now restored from its
+   * stored Stop handoff, or a dispatch put back in the queue. Reused when the
+   * entry is dispatched so the server deduplicates against that attempt — it
+   * never sees the client's abort, so a request it had already accepted still
+   * opened the chat and billed the turn. Persisted, so a retry after a reload
+   * deduplicates too.
    */
   resumeUserMessageId?: string
 }