feat: rewrite as moderation bot (Keiko)

Replaces the old AI companion bot with a full Discord moderation system.

Commands: warn, mute, unmute, kick, softban, ban, unban, prune
Logging: member join/leave, activity (messages/threads/voice), mod actions
Audit log: captures manual bans, kicks, timeouts, and unbans
Sanctions: posts to Hikari sanction API for all applicable actions

All commands are ephemeral and use Components v2. Permission and role
hierarchy checks are enforced on every applicable command.

src/events/threadDelete.ts

@@ -0,0 +1,39 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import { logActivity } from "../modules/logActivity.js";
+import { logger } from "../utils/logger.js";
+import type { AnyThreadChannel } from "discord.js";
+
+/**
+ * Logs thread deletion events to the activity log channel.
+ * @param thread - The deleted thread channel.
+ * @returns A promise that resolves when the event has been logged.
+ */
+export const onThreadDelete = async(
+  thread: AnyThreadChannel,
+): Promise<void> => {
+  try {
+    const fields = [
+      `**Thread**: ${thread.name} (\`${thread.id}\`)`,
+      `**Parent**: <#${thread.parentId ?? "Unknown"}>`,
+    ].join("\n");
+
+    await logActivity({
+      client: thread.client,
+      emoji:  "🗑️",
+      fields: fields,
+      title:  "Thread Deleted",
+    });
+  } catch (error) {
+    await logger.error(
+      "Failed to log thread delete",
+      error instanceof Error
+        ? error
+        : new Error(String(error)),
+    );
+  }
+};