Enhance welcome module with embed text rendering and autorole management

- Updated the welcome embed functionality to allow for user mentions in titles, authors, and footers, while maintaining clickable mentions in descriptions.
- Implemented autorole assignment logic with checks for role manageability and hierarchy, including detailed logging for skipped roles.
- Improved the WebUI to display real user and guild data in the welcome embed preview, enhancing user experience.
- Refactored the welcome text rendering to support additional options for mention handling based on the context of the embed fields.

apps/webui/src/components/modules/welcome-form.tsx

@@ -1,6 +1,12 @@
 'use client';
 
-import type { MessageComponentsV2, WelcomeConfigDashboard, WelcomeEmbed } from '@nexumi/shared';
+import type {
+  DashboardGuild,
+  MessageComponentsV2,
+  SessionUser,
+  WelcomeConfigDashboard,
+  WelcomeEmbed
+} from '@nexumi/shared';
 import { FieldAnchor } from '@/components/layout/field-anchor';
 import { useTranslations } from '@/components/locale-provider';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
@@ -25,16 +31,44 @@ import { Textarea } from '@/components/ui/textarea';
 import type { SettingsSaveResult } from '@/components/settings/settings-form';
 import { SettingsForm } from '@/components/settings/settings-form';
 
-const WELCOME_PREVIEW_VARS = {
-  user: '@Alex',
-  'user.name': 'Alex',
-  'user.tag': 'Alex',
-  'user.id': '123456789012345678',
-  'user.avatar': 'https://cdn.discordapp.com/embed/avatars/0.png',
-  server: 'Nexumi',
-  'server.icon': 'https://cdn.discordapp.com/embed/avatars/1.png',
-  memberCount: '128'
-};
+function discordDefaultAvatarUrl(userId: string): string {
+  try {
+    const index = Number((BigInt(userId) >> 22n) % 6n);
+    return `https://cdn.discordapp.com/embed/avatars/${index}.png`;
+  } catch {
+    return 'https://cdn.discordapp.com/embed/avatars/0.png';
+  }
+}
+
+function userAvatarUrl(user: SessionUser): string {
+  return user.avatar
+    ? `https://cdn.discordapp.com/avatars/${user.id}/${user.avatar}.png?size=256`
+    : discordDefaultAvatarUrl(user.id);
+}
+
+function guildIconUrl(guild: DashboardGuild): string {
+  return guild.icon
+    ? `https://cdn.discordapp.com/icons/${guild.id}/${guild.icon}.png?size=128`
+    : discordDefaultAvatarUrl(guild.id);
+}
+
+/** Preview placeholders from the logged-in dashboard user and current guild. */
+export function buildWelcomePreviewVars(
+  user: SessionUser,
+  guild: DashboardGuild
+): Record<string, string> {
+  const displayName = user.globalName?.trim() || user.username;
+  return {
+    user: `@${displayName}`,
+    'user.name': displayName,
+    'user.tag': user.username,
+    'user.id': user.id,
+    'user.avatar': userAvatarUrl(user),
+    server: guild.name,
+    'server.icon': guildIconUrl(guild),
+    memberCount: '—'
+  };
+}
 
 interface LocalWelcomeValue extends Omit<
   WelcomeConfigDashboard,
@@ -85,9 +119,10 @@ async function saveWelcome(guildId: string, value: LocalWelcomeValue): Promise<S
 interface WelcomeFormProps {
   guildId: string;
   initialValue: WelcomeConfigDashboard;
+  previewVars: Record<string, string>;
 }
 
-export function WelcomeForm({ guildId, initialValue }: WelcomeFormProps) {
+export function WelcomeForm({ guildId, initialValue, previewVars }: WelcomeFormProps) {
   const t = useTranslations();
 
   return (
@@ -162,7 +197,7 @@ export function WelcomeForm({ guildId, initialValue }: WelcomeFormProps) {
                   <DiscordEmbedBuilder
                     value={value.welcomeEmbed}
                     onChange={(welcomeEmbed) => setValue((prev) => ({ ...prev, welcomeEmbed }))}
-                    previewVars={WELCOME_PREVIEW_VARS}
+                    previewVars={previewVars}
                     placeholderPreset="welcome"
                   />
                 </div>
@@ -176,7 +211,7 @@ export function WelcomeForm({ guildId, initialValue }: WelcomeFormProps) {
                     guildId={guildId}
                     value={value.welcomeComponents}
                     onChange={(welcomeComponents) => setValue((prev) => ({ ...prev, welcomeComponents }))}
-                    previewVars={WELCOME_PREVIEW_VARS}
+                    previewVars={previewVars}
                     placeholderPreset="welcome"
                   />
                 </div>
@@ -312,7 +347,7 @@ export function WelcomeForm({ guildId, initialValue }: WelcomeFormProps) {
                   <DiscordEmbedBuilder
                     value={value.leaveEmbed}
                     onChange={(leaveEmbed) => setValue((prev) => ({ ...prev, leaveEmbed }))}
-                    previewVars={WELCOME_PREVIEW_VARS}
+                    previewVars={previewVars}
                     placeholderPreset="welcome"
                     titlePlaceholder={t('modulePages.welcome.leaveEmbedTitlePlaceholder')}
                     descriptionPlaceholder={t('modulePages.welcome.leaveEmbedDescriptionPlaceholder')}
@@ -328,7 +363,7 @@ export function WelcomeForm({ guildId, initialValue }: WelcomeFormProps) {
                     guildId={guildId}
                     value={value.leaveComponents}
                     onChange={(leaveComponents) => setValue((prev) => ({ ...prev, leaveComponents }))}
-                    previewVars={WELCOME_PREVIEW_VARS}
+                    previewVars={previewVars}
                     placeholderPreset="welcome"
                   />
                 </div>