feat: implement unified login flow with LoginButton and contextual LoginDialog for unauthenticated form access

app/form/[id]/page.tsx

@@ -4,6 +4,7 @@ import { getServerSession } from "next-auth";
 import { authOptions } from "@/app/api/auth/[...nextauth]/route";
 import { notFound } from "next/navigation";
 import { getGuildMemberRoles } from "@/app/actions/discord";
+import LoginDialog from "@/components/login-dialog";
 
 export const dynamic = "force-dynamic";
 
@@ -24,26 +25,29 @@ export default async function FormsSubmitPage(
     return notFound();
   }
 
-  if (discordId) {
-    const allowedRoles = form.allowedRoles || [];
-    const deniedRoles = form.deniedRoles || [];
+  const allowedRoles = form.allowedRoles || [];
+  const deniedRoles = form.deniedRoles || [];
+  const hasRoleRestrictions = allowedRoles.length > 0 || deniedRoles.length > 0;
 
-    if (allowedRoles.length > 0 || deniedRoles.length > 0) {
-      const userRoles = await getGuildMemberRoles(discordId);
-      
-      let isAllowed = allowedRoles.length === 0;
-      if (allowedRoles.length > 0) {
-        isAllowed = userRoles.some(r => allowedRoles.includes(r));
-      }
+  if (hasRoleRestrictions) {
+    if (!discordId) {
+      return notFound();
+    }
 
-      let isDenied = false;
-      if (deniedRoles.length > 0) {
-        isDenied = userRoles.some(r => deniedRoles.includes(r));
-      }
+    const userRoles = await getGuildMemberRoles(discordId);
+    
+    let isAllowed = allowedRoles.length === 0;
+    if (allowedRoles.length > 0) {
+      isAllowed = userRoles.some(r => allowedRoles.includes(r));
+    }
 
-      if (!isAllowed || isDenied) {
-        return notFound();
-      }
+    let isDenied = false;
+    if (deniedRoles.length > 0) {
+      isDenied = userRoles.some(r => deniedRoles.includes(r));
+    }
+
+    if (!isAllowed || isDenied) {
+      return notFound();
     }
   }
 
@@ -70,12 +74,15 @@ export default async function FormsSubmitPage(
   }
 
   return (
-    <div className="max-w-2xl mx-auto p-4 md:p-6 space-y-6">
-      <FormFillerClient 
-        form={form} 
-        questions={questionsList} 
-        initialAnswers={initialAnswers} 
-      />
-    </div>
+    <>
+      <div className="max-w-2xl mx-auto p-4 md:p-6 space-y-6">
+        <FormFillerClient 
+          form={form} 
+          questions={questionsList} 
+          initialAnswers={initialAnswers} 
+        />
+      </div>
+      {!discordId && <LoginDialog />}
+    </>
   );
 }