fix(web): simplify first-time token sign-in

web/src/components/auth/auth-screen.tsx

@@ -26,7 +26,7 @@ export function AuthScreen({ authTokenInput, setAuthTokenInput, isSigningIn, aut
           </div>
           <div>
             <h1 className="text-lg font-semibold text-violet-50">Sign in to Sybil</h1>
-            <p className="mt-1 text-sm text-muted-foreground">Use your backend admin token.</p>
+            <p className="mt-1 text-sm text-muted-foreground">Enter your admin token.</p>
           </div>
         </div>
 
@@ -34,28 +34,27 @@ export function AuthScreen({ authTokenInput, setAuthTokenInput, isSigningIn, aut
           className="space-y-3"
           onSubmit={(event) => {
             event.preventDefault();
-            void onSignIn(authTokenInput.trim() || null);
+            const token = authTokenInput.trim();
+            if (token) void onSignIn(token);
           }}
         >
           <Input
             type="password"
             autoComplete="off"
+            aria-label="Admin token"
             placeholder="ADMIN_TOKEN"
+            required
             value={authTokenInput}
             onInput={(event) => setAuthTokenInput(event.currentTarget.value)}
             disabled={isSigningIn}
             className="bg-[hsl(235_48%_6%_/_0.84)] text-violet-50"
           />
-          <Button className="w-full" type="submit" disabled={isSigningIn}>
+          <Button className="w-full" type="submit" disabled={isSigningIn || !authTokenInput.trim()}>
             {isSigningIn ? "Signing in..." : "Sign in"}
           </Button>
-          <Button className="w-full" type="button" variant="secondary" disabled={isSigningIn} onClick={() => void onSignIn(null)}>
-            Continue without token
-          </Button>
         </form>
 
-        {authError ? <p className="mt-3 text-sm text-red-600">{authError}</p> : null}
-        <p className="mt-3 text-xs text-muted-foreground">If `ADMIN_TOKEN` is set in `/server/.env`, token login is required.</p>
+        {authError ? <p role="alert" className="mt-3 text-sm text-red-600">{authError}</p> : null}
       </div>
     </div>
   );