feat: add login button to header and conditional edit UI

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/client/components/TotalsBar.tsx

@@ -1,4 +1,5 @@
 import { Link } from "@tanstack/react-router";
+import { useAuth, useLogout } from "../hooks/useAuth";
 import { useUpdateSetting } from "../hooks/useSettings";
 import { useTotals } from "../hooks/useTotals";
 import { useWeightUnit } from "../hooks/useWeightUnit";
@@ -19,6 +20,9 @@ export function TotalsBar({
 	linkTo,
 }: TotalsBarProps) {
 	const { data } = useTotals();
+	const { data: auth } = useAuth();
+	const logout = useLogout();
+	const isAuthenticated = !!auth?.user;
 	const unit = useWeightUnit();
 	const updateSetting = useUpdateSetting();
 
@@ -100,6 +104,24 @@ export function TotalsBar({
 								))}
 							</div>
 						)}
+						<div className="flex items-center gap-2 ml-auto">
+							{isAuthenticated ? (
+								<button
+									type="button"
+									onClick={() => logout.mutate()}
+									className="text-xs text-gray-500 hover:text-gray-700 transition-colors"
+								>
+									Sign out
+								</button>
+							) : (
+								<Link
+									to="/login"
+									className="text-xs text-gray-500 hover:text-gray-700 transition-colors"
+								>
+									Sign in
+								</Link>
+							)}
+						</div>
 					</div>
 				</div>
 			</div>

src/client/routes/__root.tsx

@@ -13,6 +13,7 @@ import { ItemForm } from "../components/ItemForm";
 import { OnboardingWizard } from "../components/OnboardingWizard";
 import { SlideOutPanel } from "../components/SlideOutPanel";
 import { TotalsBar } from "../components/TotalsBar";
+import { useAuth } from "../hooks/useAuth";
 import { useDeleteCandidate } from "../hooks/useCandidates";
 import { useOnboardingComplete } from "../hooks/useSettings";
 import { useResolveThread, useThread } from "../hooks/useThreads";
@@ -24,6 +25,8 @@ export const Route = createRootRoute({
 
 function RootLayout() {
 	const navigate = useNavigate();
+	const { data: auth } = useAuth();
+	const isAuthenticated = !!auth?.user;
 
 	// Item panel state
 	const panelMode = useUIStore((s) => s.panelMode);
@@ -175,7 +178,7 @@ function RootLayout() {
 			)}
 
 			{/* Floating Add Button - only on collection gear tab */}
-			{showFab && (
+			{showFab && isAuthenticated && (
 				<button
 					type="button"
 					onClick={openAddPanel}