refactor(ui): QueryaIconButton and QueryaButton.icon are two icon-button systems #1440

Problem

QueryaIconButton (26 call sites, Material ink and its own hover) and QueryaButton.icon (16 call sites, no ripple, the standard's states) look and react differently next to each other, for example in the SQL toolbar and in the results bar.

Scope

• Make QueryaIconButton a thin wrapper over QueryaButton.icon (isActive, isDestructive, color / activeColor map to variant and tone), keeping density as the sm / md alias.
• Move the call sites over, then remove the Material InkWell path.
• Keep the 2 px keyboard focus ring and the selected semantics added in fix(a11y): focus ring and state semantics for QueryaIconButton #1395.

Found while driving a Linux debug build of dev after the button migration (UI consistency review). Part of epic #1331.