feat(31-02): add responsive icon buttons to setup detail page

Replace text action buttons (Add Items, Public/Private toggle, Delete
Setup) with icon-only buttons on mobile. Migrate inline SVGs to
LucideIcon component (plus, globe, trash-2). All icon buttons have
aria-label and 44px touch targets.

src/client/routes/setups/$setupId.tsx

@@ -154,59 +154,73 @@ function SetupDetailPage() {
 			{/* Actions — only visible to authenticated users */}
 			{isAuthenticated && (
 				<div className="flex items-center gap-3 py-4">
+					{/* Add Items — desktop */}
 					<button
 						type="button"
 						onClick={() => setPickerOpen(true)}
-						className="inline-flex items-center gap-2 px-4 py-2 bg-gray-700 hover:bg-gray-800 text-white text-sm font-medium rounded-lg transition-colors"
+						className="hidden md:inline-flex items-center gap-2 px-4 py-2 bg-gray-700 hover:bg-gray-800 text-white text-sm font-medium rounded-lg transition-colors"
 					>
-						<svg
+						<LucideIcon name="plus" size={16} />
-							className="w-4 h-4"
-							fill="none"
-							stroke="currentColor"
-							viewBox="0 0 24 24"
-						>
-							<path
-								strokeLinecap="round"
-								strokeLinejoin="round"
-								strokeWidth={2}
-								d="M12 4v16m8-8H4"
-							/>
-						</svg>
 						Add Items
 					</button>
+					{/* Add Items — mobile */}
+					<button
+						type="button"
+						onClick={() => setPickerOpen(true)}
+						className="md:hidden inline-flex items-center justify-center min-w-[44px] min-h-[44px] p-2 bg-gray-700 hover:bg-gray-800 text-white rounded-lg transition-colors"
+						aria-label="Add Items"
+						title="Add Items"
+					>
+						<LucideIcon name="plus" size={16} />
+					</button>
 
-					{/* Public toggle */}
+					{/* Public toggle — desktop */}
 					<button
 						type="button"
 						onClick={() => updateSetup.mutate({ isPublic: !setup.isPublic })}
-						className={`inline-flex items-center gap-1.5 px-3 py-2 text-sm font-medium rounded-lg transition-colors ${
+						className={`hidden md:inline-flex items-center gap-1.5 px-3 py-2 text-sm font-medium rounded-lg transition-colors ${
 							setup.isPublic
 								? "text-green-700 bg-green-50 hover:bg-green-100"
 								: "text-gray-500 bg-gray-50 hover:bg-gray-100"
 						}`}
 					>
-						<svg
+						<LucideIcon name="globe" size={16} />
-							className="w-4 h-4"
-							fill="none"
-							stroke="currentColor"
-							viewBox="0 0 24 24"
-							strokeWidth={1.5}
-						>
-							<circle cx="12" cy="12" r="10" />
-							<path d="M2 12h20" />
-							<path d="M12 2a15.3 15.3 0 0 1 4 10 15.3 15.3 0 0 1-4 10 15.3 15.3 0 0 1-4-10 15.3 15.3 0 0 1 4-10z" />
-						</svg>
 						{setup.isPublic ? "Public" : "Private"}
 					</button>
+					{/* Public toggle — mobile */}
+					<button
+						type="button"
+						onClick={() => updateSetup.mutate({ isPublic: !setup.isPublic })}
+						className={`md:hidden inline-flex items-center justify-center min-w-[44px] min-h-[44px] p-2 rounded-lg transition-colors ${
+							setup.isPublic
+								? "text-green-700 bg-green-50 hover:bg-green-100"
+								: "text-gray-500 bg-gray-50 hover:bg-gray-100"
+						}`}
+						aria-label={setup.isPublic ? "Public" : "Private"}
+						title={setup.isPublic ? "Public" : "Private"}
+					>
+						<LucideIcon name="globe" size={16} />
+					</button>
 
 					<div className="flex-1" />
+					{/* Delete Setup — desktop */}
 					<button
 						type="button"
 						onClick={() => setConfirmDelete(true)}
-						className="inline-flex items-center gap-2 px-4 py-2 text-sm font-medium text-red-600 bg-red-50 hover:bg-red-100 rounded-lg transition-colors"
+						className="hidden md:inline-flex items-center gap-2 px-4 py-2 text-sm font-medium text-red-600 bg-red-50 hover:bg-red-100 rounded-lg transition-colors"
 					>
 						Delete Setup
 					</button>
+					{/* Delete Setup — mobile */}
+					<button
+						type="button"
+						onClick={() => setConfirmDelete(true)}
+						className="md:hidden inline-flex items-center justify-center min-w-[44px] min-h-[44px] p-2 text-red-600 bg-red-50 hover:bg-red-100 rounded-lg transition-colors"
+						aria-label="Delete Setup"
+						title="Delete Setup"
+					>
+						<LucideIcon name="trash-2" size={16} />
+					</button>
 				</div>
 			)}