Scan projects a stale schema after a schema update with no write

### Apache Iceberg Rust version

None

### Describe the bug

Schema updates don't create snapshots. So after ADD COLUMN with no write since, the current snapshot still references the older schema — and scanning the current state used it:

// table (id, name) with a row written, then a column added
table.scan().select(["email"]).build() // Err: Column email not found in table
table.scan().select_all().build() // silently returns only (id, name)

email is a real column on the table, but invisible to the scan. Any subsequent write hides the problem, which is why it went unnoticed.

### To Reproduce

for an existing table, add a column, then try to read from that column (error)

### Expected behavior

Should return column with null

### Willingness to contribute

I can contribute a fix for this bug independently

Start by reproducing the issue with an existing table: write a row, add a column without writing again, then run table.scan().select(["email"]).build() and table.scan().select_all().build(). Trace how these scan entry points choose the schema; done means the new column is visible and returns null when it has no values.

Written by the indexing model from the issue text.