Implement leave announcement for banned members and enhance moderation notifications

- Added a `leaveAnnounceBan` field to the `WelcomeConfig` model, allowing for optional announcements in the leave channel when a member is banned.
- Updated the leave handling logic to check for bans and send a notice in the leave channel if the `leaveAnnounceBan` toggle is enabled.
- Enhanced moderation actions (kick and ban) to notify the affected user via DM with the reason for the action.
- Introduced a new `notifyModerationTargetDm` function to streamline DM notifications for moderation actions.
- Updated the WebUI to include a toggle for the `leaveAnnounceBan` feature, improving user configurability.
- Improved localization for new messages related to moderation notifications and leave announcements in both English and German.
- Documented changes in phase tracking to reflect the new leave announcement feature and moderation notification enhancements.

apps/bot/src/modules/moderation/commands.ts

@@ -8,7 +8,7 @@ import { t, tf } from '@nexumi/shared';
 import type { SlashCommand } from '../../types.js';
 import { requirePermission } from '../../permissions.js';
 import { assertModerableMember } from '../../hierarchy.js';
-import { applyWarnEscalation, createCase, createWarning } from './service.js';
+import { applyWarnEscalation, createCase, createWarning, notifyModerationTargetDm } from './service.js';
 import { parseDuration, parseTimeoutDuration, tryParseDuration } from './duration.js';
 import { getGuildLocale } from '../../i18n.js';
 import { promptDestructiveConfirmation } from './confirmations.js';
@@ -133,6 +133,13 @@ const kickCommand: SlashCommand = {
     const reason = reasonFrom(interaction, locale);
     const hierarchy = await assertModerableMember(interaction, user.id, locale, 'kick');
     if (!hierarchy.ok || !hierarchy.member) return;
+    await notifyModerationTargetDm({
+      user,
+      guildName: interaction.guild!.name,
+      reason,
+      locale,
+      action: 'kick'
+    });
     await hierarchy.member.kick(reason);
     const modCase = await createCase(context, {
       guildId: interaction.guildId!,