A run of small quality fixes in the studio.

The assets back button now re-squares the cached gallery instance when you activate the tab, so returning to Assets never leaves you looking at a stale view of what is there. The gen feed's prompt row is back after a brief absence, this time rebuilt on the canonical row shape so it matches everything else in the feed. And in every chat surface where Voysey shows its reasoning, the reasoning stream now forwards to the client cleanly, so intermediate thinking bubbles up as it is written instead of arriving all at once at the end (or dropping silently in the middle).