Chat top fade round 1 (owner): long soft wash instead of a hard 20px bar

The header fade was h-5 (20px) from full background opacity — it
read as a solid bar with a quick blur on the edge. Now a 96px wash:
65% under the title, holding softly through ~25% at the midpoint,
melting to transparent — supports the title, never reads as a bar.

components/chat.tsx

@@ -485,11 +485,13 @@ export function Chat({
 					<SidebarToggle />
 					<div className="min-w-0 flex-1 truncate font-title text-2xl tracking-tight">{title}</div>
 					<PhaseChip phase={phases.at(-1) ?? "probe"} />
-					{/* Soft top fade (owner): the scroller edge under the header eases
-					    in exactly like the dock gradient at the bottom. */}
+					{/* Soft top fade (owner, round 1 of the fade rework): a long wash
+					    that holds softly under the title then melts away — no full
+					    opacity anywhere, so it supports the header instead of reading
+					    as a bar. */}
 					<div
 						aria-hidden
-						className="pointer-events-none absolute inset-x-0 top-full z-10 h-5 bg-gradient-to-b from-background to-transparent"
+						className="pointer-events-none absolute inset-x-0 top-full z-10 h-24 bg-gradient-to-b from-background/65 via-background/25 to-transparent"
 					/>
 				</header>