wizard: skip cell-name and domain steps when installer pre-configured them

When the bash installer collects cell name and domain mode, the first-run
wizard's /setup should only ask for a password, service selection, and
timezone.  Previously the wizard pre-filled those fields but still showed
all 7 steps.

- useEffect fetches /api/setup/status on mount; if preconfigured.cell_name
  and preconfigured.domain_mode are both set, sets installerConfigured=true
  and jumps to step 2 (password)
- handleStep2Next → step 5 when installerConfigured (skips domain steps 3+4)
- handleStep2Back → step 1 when installerConfigured (review cell name)
- handleStep5Back returns to step 2 when installerConfigured

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

webui/src/pages/Setup.jsx

@@ -789,13 +789,16 @@ export default function Setup() {
   const [submitting, setSubmitting] = useState(false);
   const [submitError, setSubmitError] = useState('');
 
-  // Pre-fill from installer config if present
+  // True when the bash installer already configured cell identity
+  const [installerConfigured, setInstallerConfigured] = useState(false);
+
+  // Pre-fill from installer config; if cell + domain already set, jump to password step
   useEffect(() => {
     setupAPI.getStatus()
       .then(res => {
         const pre = res.data?.preconfigured;
         if (!pre) return;
-        if (pre.cell_name)  setCellName(pre.cell_name);
+        if (pre.cell_name) setCellName(pre.cell_name);
         if (pre.domain_mode) {
           if      (pre.domain_mode === 'pic_ngo') setDomainType('pic_ngo');
           else if (pre.domain_mode === 'lan')     setDomainType('lan');
@@ -804,6 +807,10 @@ export default function Setup() {
         if (pre.domain_name)          setCustomDomain(pre.domain_name);
         if (pre.cloudflare_api_token) setCloudflareToken(pre.cloudflare_api_token);
         if (pre.duckdns_token)        setDuckdnsToken(pre.duckdns_token);
+        if (pre.cell_name && pre.domain_mode) {
+          setInstallerConfigured(true);
+          setStep(2); // skip cell name + domain steps — already done by installer
+        }
       })
       .catch(() => {}); // fail silently — wizard works from scratch
   }, []);
@@ -813,9 +820,13 @@ export default function Setup() {
   const goNext = () => setStep(s => Math.min(s + 1, TOTAL_STEPS));
   const goBack = () => setStep(s => Math.max(s - 1, 1));
 
+  // When installer pre-configured identity: step 2 → step 5 (skip domain steps)
+  const handleStep2Next = () => installerConfigured ? setStep(5) : goNext();
+  const handleStep2Back = () => installerConfigured ? setStep(1) : goBack();
+
   const handleStep3Next = () => skipStep4 ? setStep(5) : setStep(4);
   const handleStep4Back = () => setStep(3);
-  const handleStep5Back = () => skipStep4 ? setStep(3) : setStep(4);
+  const handleStep5Back = () => installerConfigured ? setStep(2) : skipStep4 ? setStep(3) : setStep(4);
 
   const handleSubmit = async () => {
     setSubmitError('');
@@ -896,8 +907,8 @@ export default function Setup() {
             confirm={passwordConfirm}
             onChangePassword={setPassword}
             onChangeConfirm={setPasswordConfirm}
-            onNext={goNext}
-            onBack={goBack}
+            onNext={handleStep2Next}
+            onBack={handleStep2Back}
           />
         )}
         {step === 3 && (