Dolt rejects a repeated window expression in `ORDER BY` as ambiguous.

## What happened

Dolt rejects a direct repetition of a window expression in the same query's `ORDER BY` with an ambiguous column/alias resolution error.

MySQL accepts the repeated expression and returns rows ordered by the window value.

## Environment

Dolt main at commit `a995f245c032bc412aed308194d81ee12bc74f19` (`dolt version 2.2.3`).

## How to reproduce

In a fresh Dolt repository, run:

```sql
CREATE TABLE t(id INT PRIMARY KEY, g INT, v INT NOT NULL);

INSERT INTO t VALUES (1, 0, 10), (2, 0, -2);

SELECT id, g,
SUM(v) OVER (
PARTITION BY g ORDER BY id ASC
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
) AS wf
FROM t
ORDER BY SUM(v) OVER (
PARTITION BY g ORDER BY id ASC
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
), id;
```

## Expected result

MySQL 8.0.43 returns:

```text
id g wf
2 0 8
1 0 10
```

## Actual result

The source repeats the running `SUM` window expression directly in `ORDER BY`. It fails with:

```text
ambiguous column or alias name "sum ... over (...) ... t.v"
```