Update fun module configuration and enhance CSS styles

- Added 'enabled' property to FunConfigSchema with a default value of true for better configuration management.
- Refactored getFunConfig to return a complete default configuration when no data is found.
- Improved globals.css by expanding CSS variables for light and dark themes, enhancing styling consistency across the application.

apps/webui/src/lib/guilds.ts

@@ -0,0 +1,51 @@
+import { hasManageGuildPermission, type DashboardGuild } from '@nexumi/shared';
+import { fetchDiscordUserGuildsCached } from './discord-oauth';
+import { prisma } from './prisma';
+import type { SessionPayload } from './session';
+
+/**
+ * Returns the guilds the current session user can manage (Manage Guild
+ * permission), enriched with whether Nexumi is already installed there.
+ * Guilds where the bot is present are sorted first.
+ */
+export async function getManageableGuilds(session: SessionPayload): Promise<DashboardGuild[]> {
+  const discordGuilds = await fetchDiscordUserGuildsCached(session.accessToken);
+  const manageable = discordGuilds.filter((guild) => hasManageGuildPermission(guild.permissions));
+
+  if (manageable.length === 0) {
+    return [];
+  }
+
+  const presentGuilds = await prisma.guild.findMany({
+    where: { id: { in: manageable.map((guild) => guild.id) } },
+    select: { id: true }
+  });
+  const presentIds = new Set(presentGuilds.map((guild) => guild.id));
+
+  return manageable
+    .map<DashboardGuild>((guild) => ({
+      id: guild.id,
+      name: guild.name,
+      icon: guild.icon,
+      botPresent: presentIds.has(guild.id),
+      permissions: guild.permissions
+    }))
+    .sort((a, b) => {
+      if (a.botPresent !== b.botPresent) {
+        return a.botPresent ? -1 : 1;
+      }
+      return a.name.localeCompare(b.name);
+    });
+}
+
+/**
+ * Looks up a single manageable guild by id, or null when the session user
+ * does not manage it.
+ */
+export async function getManageableGuild(
+  session: SessionPayload,
+  guildId: string
+): Promise<DashboardGuild | null> {
+  const guilds = await getManageableGuilds(session);
+  return guilds.find((guild) => guild.id === guildId) ?? null;
+}