refactor: saasMode 분기 제거 — 항상 SaaS(OAuth only)로 동작

Mac/Windows 환경 불일치 해소. BUILD_TIME 상수, CONFIGURE 채널,
개발자 모드 UI 전부 제거. Supabase 설정은 supabase-config.ts SSOT.

apps/desktop/src/renderer/components/OnboardingModal.tsx

@@ -36,8 +36,6 @@ export function OnboardingModal({ open, onClose }: OnboardingModalProps): React.
   const [selectedDevice, setSelectedDevice] = useState('default')
   const [hotkeyBinding, setHotkeyBinding] = useState<HotkeyBinding | null>(null)
   const [hotkeyModalOpen, setHotkeyModalOpen] = useState(false)
-  const [saasMode, setSaasMode] = useState(false)
-
   useEffect(() => {
     if (!open) return
     setStep(0)
@@ -47,10 +45,6 @@ export function OnboardingModal({ open, onClose }: OnboardingModalProps): React.
     window.electronAPI.hotkey.getDictationShortcut().then((r) => {
       if (r.success && r.data) setHotkeyBinding(r.data)
     })
-    // Cloud Sync step은 빌드 타임 Supabase env가 있을 때만 의미가 있음
-    window.electronAPI.cloudSync.getState().then((r) => {
-      if (r.success) setSaasMode(r.data.saasMode)
-    })
   }, [open])
 
   const handleFinish = (): void => {
@@ -59,9 +53,9 @@ export function OnboardingModal({ open, onClose }: OnboardingModalProps): React.
     onClose()
   }
 
-  // Ollama step(3) 다음 — saasMode면 Cloud Sync step(4), 아니면 바로 완료(5)로
+  // Ollama step(3) 다음 → Cloud Sync step(4)로
   const nextAfterOllama = (): void => {
-    setStep(saasMode ? 4 : 5)
+    setStep(4)
   }
 
   // Cloud Sync step에서 Back 누르면 Ollama(3)로 복귀
@@ -256,7 +250,7 @@ export function OnboardingModal({ open, onClose }: OnboardingModalProps): React.
             </Box>
           )}
 
-          {/* Step 4: Cloud Sync (선택, saasMode에서만 노출) */}
+          {/* Step 4: Cloud Sync (선택) */}
           {step === 4 && (
             <Box>
               <Stack direction="row" alignItems="center" gap={1} mb={3}>