Loading data into the same namespace does not replace the table

[mhkeller]

Using the fix from #232, I thought I could clear the cache and replace data in a table by using the replace: true option on vg.loadParquet but the old data doesn't seem to go away. I made a repro on the 2025-10 branch here.

If I use a different table name it works fine, which I can implement on my end, but I wasn't sure if this was the expected behavior.