Electric collection mutations fail to wait for array of txids

[godiagonal]

• I've validated the bug against the latest version of DB packages

Describe the bug
I'm experiencing an issue with awaiting multiple txids in an electric collection mutation handler. I'm getting a TimeoutWaitingForTxIdError as soon as one of the txids are seen on the stream, even though I'm well below the timeout.

To Reproduce

Define a collection like this:

const todosCollection = createCollection(
 electricCollectionOptions({
 id: 'todos',
 getKey: (item) => item.id,
 shapeOptions: {
 url: '/api/todos',
 params: { table: 'todos' },
 },
 onInsert: async ({ transaction }) => {
 const txids = await Promise.all(
 transaction.mutations.map((mutation) =>
 api.todos.create(mutation.modified),
 )
 );

 return { txid: txids };
 }
 })
)

Run a mutation (single or multiple entries):

// ❌ Throws TimeoutWaitingForTxIdError before 5 second timeout
todosCollection.insert({ id: crypto.randomUUID(), title: 'New todo' })

// ❌ Throws TimeoutWaitingForTxIdError before 5 second timeout
todosCollection.insert([{ id: crypto.randomUUID(), title: 'New todo 1' }, { id: crypto.randomUUID(), title: 'New todo 2' }])

Expected behavior
I expect the mutations not to throw TimeoutWaitingForTxIdError unless the transaction takes > 5 seconds to appear on stream.

Desktop (please complete the following information):

• OS: MacOS
• Browser: Chrome
• Version: 141.0.7390.123

Additional context
The waiting works fine when returning a single txid instead of a txid array in mutation handler.

This modification to processMatchingStrategy fixes the issue:

await Promise.all(result.txid.map((txid) => awaitTxId(txid)))