Display table row count.

[igalklebanov]

Hey 👋

Originally raised in #1354.

Display table row count.

We already retrieve it from the database for pagination calculation, so it should be an easy win.

[sorenbs]

Hey @igalklebanov 👋 Implemented in #1554 — the grid footer now shows the row count (e.g. "4,725 rows") reusing the count that already drives pagination, so it reflects active filters and search with no extra queries, stays exact past Number.MAX_SAFE_INTEGER via BigInt, and hides when the adapter can't count.