fix: clear filter state when no tab is selected after close

[datlechin]

Summary

• Fix stale filter pane persisting after FK navigation tab is closed
• When handleTabChange transitions to no tab (newTabId == nil), filterStateManager.clearAll() was never called, leaving isVisible = true and stale FK filters on the coordinator-level state
• Opening a new table after this would show the filter pane with the old FK filter

Root cause: FilterStateManager.isVisible is coordinator-level (not per-tab). setFKFilter() sets isVisible = true, but the nil-tab branch in handleTabChange never reset it.

Test plan

• Open a table with FK columns
• Cmd+Enter on FK cell → click "Open {table}" → filter pane opens with FK filter
• Close the FK-navigated tab (Cmd+W)
• Open any other table → filter pane should be closed, no stale filters