This improves the user experience by automatically filling the email field

and preventing users from changing the email they were invited with.

- Update invite link generation to include email parameter in URL
- Modify signup form to pre-fill and lock email field when provided via invite
- Update invite page and status card to preserve email through redirect chain
- Ensure existing invite URLs continue to work without breaking changes

server/routers/user/inviteUser.ts

@@ -189,7 +189,7 @@ export async function inviteUser(
                     )
                 );
 
-            const inviteLink = `${config.getRawConfig().app.dashboard_url}/invite?token=${inviteId}-${token}`;
+            const inviteLink = `${config.getRawConfig().app.dashboard_url}/invite?token=${inviteId}-${token}&email=${encodeURIComponent(email)}`;
 
             if (doEmail) {
                 await sendEmail(
@@ -241,7 +241,7 @@ export async function inviteUser(
             });
         });
 
-        const inviteLink = `${config.getRawConfig().app.dashboard_url}/invite?token=${inviteId}-${token}`;
+        const inviteLink = `${config.getRawConfig().app.dashboard_url}/invite?token=${inviteId}-${token}&email=${encodeURIComponent(email)}`;
 
         if (doEmail) {
             await sendEmail(

src/app/auth/signup/SignupForm.tsx

@@ -75,6 +75,7 @@ type SignupFormProps = {
     redirect?: string;
     inviteId?: string;
     inviteToken?: string;
+    emailParam?: string;
 };
 
 const formSchema = z
@@ -103,7 +104,8 @@ const formSchema = z
 export default function SignupForm({
     redirect,
     inviteId,
-    inviteToken
+    inviteToken,
+    emailParam
 }: SignupFormProps) {
     const router = useRouter();
     const api = createApiClient(useEnvContext());
@@ -118,7 +120,7 @@ export default function SignupForm({
     const form = useForm<z.infer<typeof formSchema>>({
         resolver: zodResolver(formSchema),
         defaultValues: {
-            email: "",
+            email: emailParam || "",
             password: "",
             confirmPassword: "",
             agreeToTerms: false
@@ -209,7 +211,10 @@ export default function SignupForm({
                                 <FormItem>
                                     <FormLabel>{t("email")}</FormLabel>
                                     <FormControl>
-                                        <Input {...field} />
+                                        <Input 
+                                            {...field} 
+                                            disabled={!!emailParam}
+                                        />
                                     </FormControl>
                                     <FormMessage />
                                 </FormItem>

src/app/auth/signup/page.tsx

@@ -11,7 +11,10 @@ import { getTranslations } from "next-intl/server";
 export const dynamic = "force-dynamic";
 
 export default async function Page(props: {
-    searchParams: Promise<{ redirect: string | undefined }>;
+    searchParams: Promise<{ 
+        redirect: string | undefined;
+        email: string | undefined;
+    }>;
 }) {
     const searchParams = await props.searchParams;
     const getUser = cache(verifySession);
@@ -69,6 +72,7 @@ export default async function Page(props: {
                 redirect={redirectUrl}
                 inviteToken={inviteToken}
                 inviteId={inviteId}
+                emailParam={searchParams.email}
             />
 
             <p className="text-center text-muted-foreground mt-4">

src/app/invite/InviteStatusCard.tsx

@@ -17,11 +17,13 @@ import { useTranslations } from "next-intl";
 type InviteStatusCardProps = {
     type: "rejected" | "wrong_user" | "user_does_not_exist" | "not_logged_in";
     token: string;
+    email?: string;
 };
 
 export default function InviteStatusCard({
     type,
     token,
+    email,
 }: InviteStatusCardProps) {
     const router = useRouter();
     const api = createApiClient(useEnvContext());
@@ -29,12 +31,18 @@ export default function InviteStatusCard({
 
     async function goToLogin() {
         await api.post("/auth/logout", {});
-        router.push(`/auth/login?redirect=/invite?token=${token}`);
+        const redirectUrl = email 
+            ? `/auth/login?redirect=/invite?token=${token}&email=${encodeURIComponent(email)}`
+            : `/auth/login?redirect=/invite?token=${token}`;
+        router.push(redirectUrl);
     }
 
     async function goToSignup() {
         await api.post("/auth/logout", {});
-        router.push(`/auth/signup?redirect=/invite?token=${token}`);
+        const redirectUrl = email 
+            ? `/auth/signup?redirect=/invite?token=${token}&email=${encodeURIComponent(email)}`
+            : `/auth/signup?redirect=/invite?token=${token}`;
+        router.push(redirectUrl);
     }
 
     function renderBody() {

src/app/invite/page.tsx

@@ -14,6 +14,7 @@ export default async function InvitePage(props: {
     const params = await props.searchParams;
 
     const tokenParam = params.token as string;
+    const emailParam = params.email as string;
 
     if (!tokenParam) {
         redirect("/");
@@ -70,16 +71,22 @@ export default async function InvitePage(props: {
     const type = cardType();
 
     if (!user && type === "user_does_not_exist") {
-        redirect(`/auth/signup?redirect=/invite?token=${params.token}`);
+        const redirectUrl = emailParam 
+            ? `/auth/signup?redirect=/invite?token=${params.token}&email=${encodeURIComponent(emailParam)}`
+            : `/auth/signup?redirect=/invite?token=${params.token}`;
+        redirect(redirectUrl);
     }
 
     if (!user && type === "not_logged_in") {
-        redirect(`/auth/login?redirect=/invite?token=${params.token}`);
+        const redirectUrl = emailParam 
+            ? `/auth/login?redirect=/invite?token=${params.token}&email=${encodeURIComponent(emailParam)}`
+            : `/auth/login?redirect=/invite?token=${params.token}`;
+        redirect(redirectUrl);
     }
 
     return (
         <>
-            <InviteStatusCard type={type} token={tokenParam} />
+            <InviteStatusCard type={type} token={tokenParam} email={emailParam} />
         </>
     );
 }