[Bug]: Split Transaction Rule not calculating properly

### What happened?

I've had a rule in place that splits a transaction from this vendor so that split 1 allocates $85 to one category and allocates 100% of the remainder to the second category. This rule has worked fine historically. I installed 26.6.0 and performed a bank sync. The two new transactions from this vendor split BUT added the $85 to the transaction amount and made the second split the sum of the two. E.g. Transaction $100, Split 1 $85, Split 2 $185. If I try to delete Split 2 and redistribute the correct amount ($15) then it thinks that the larger Split 2 amount ($185) was the transaction total and tells me I have the difference to still distribute. I deleted the rule thinking I had set it incorrectly even though its worked fine previously, re-synced those transactions and I could edit the split as expected. I then tried a rule for split 2 to use an equal portion of the remainder and the same issue occurred.

### How can we reproduce the issue?

Create a Rule to split a transaction. Split 1 should be a set value and Split 2 should allocate the remainder.

### Where are you hosting Actual?

Docker

### What browsers are you seeing the problem on?

Chrome

### Operating System

Windows 11

No source file or test is named. First reproduce the split-rule case in Chrome with Actual hosted in Docker: set one split to a fixed amount and the other to the remainder, then sync a matching transaction. Trace the transaction split-rule calculation and verify that the splits total the original transaction amount and remain editable.

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