Migrate icon buttons to Button component and simplify size variants

Replace raw <button> elements with Button variant="ghost" in stat-block
panel, toast, player modals. Add icon-sm size variant (h-6 w-6) for
compact contexts. Consolidate text button sizes into a single default
(h-8 px-3), removing the redundant sm variant. Add size prop to
ConfirmButton for consistent sizing.

Button now has three sizes: default (text), icon, icon-sm.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/components/ui/confirm-button.tsx

@@ -13,6 +13,7 @@ interface ConfirmButtonProps {
 	readonly onConfirm: () => void;
 	readonly icon: ReactElement;
 	readonly label: string;
+	readonly size?: "icon" | "icon-sm";
 	readonly className?: string;
 	readonly disabled?: boolean;
 }
@@ -23,6 +24,7 @@ export function ConfirmButton({
 	onConfirm,
 	icon,
 	label,
+	size = "icon",
 	className,
 	disabled,
 }: ConfirmButtonProps) {
@@ -94,7 +96,7 @@ export function ConfirmButton({
 		<div ref={wrapperRef} className="inline-flex">
 			<Button
 				variant="ghost"
-				size="icon"
+				size={size}
 				className={cn(
 					className,
 					isConfirming