Desktop register: validate email format client-side and disable submit to avoid 400

apps/desktop/src/main.tsx

@@ -207,6 +207,8 @@ function App() {
   const autoLaunchRef = useRef(false)
   const autoUpdateRef = useRef(false)
   const logoFallbackRef = useRef(false)
+  const emailRegex = useRef(/^[^\s@]+@[^\s@]+\.[^\s@]{2,}$/i)
+  const isEmailValid = useMemo(() => emailRegex.current.test(collabEmail.trim()), [collabEmail])
 
   useEffect(() => {
     (async () => {
@@ -449,6 +451,10 @@ function App() {
       setError("Informe o e-mail do colaborador vinculado a esta máquina.")
       return
     }
+    if (!emailRegex.current.test(normalizedEmail)) {
+      setError("Informe um e-mail válido (ex.: nome@empresa.com)")
+      return
+    }
     const normalizedName = collabName.trim()
     if (!normalizedName) {
       setError("Informe o nome completo do colaborador.")
@@ -837,10 +843,14 @@ function App() {
               </label>
               <input
                 className="w-full rounded-lg border border-slate-300 px-3 py-2 text-sm"
+                type="email"
                 placeholder="colaborador@empresa.com"
                 value={collabEmail}
                 onChange={(e) => setCollabEmail(e.target.value)}
               />
+              {collabEmail && !isEmailValid ? (
+                <p className="text-xs text-rose-600">Informe um e-mail válido (ex.: nome@empresa.com)</p>
+              ) : null}
             </div>
             <div className="grid gap-2">
               <label className="text-sm font-medium">
@@ -874,7 +884,7 @@ function App() {
               </div>
             ) : null}
             <div className="mt-2 flex gap-2">
-              <button disabled={busy || !validatedCompany} onClick={register} className="rounded-lg border border-black bg-black px-3 py-2 text-sm font-semibold text-white hover:bg-black/90 disabled:opacity-60">Registrar máquina</button>
+              <button disabled={busy || !validatedCompany || !isEmailValid || !collabName.trim() || provisioningCode.trim().length < 32} onClick={register} className="rounded-lg border border-black bg-black px-3 py-2 text-sm font-semibold text-white hover:bg-black/90 disabled:opacity-60">Registrar máquina</button>
             </div>
           </div>
         ) : (