feat: implement activity logging for user actions and create activities table

app/services/activity_logger.ts

@@ -0,0 +1,27 @@
+// app/services/activity_logger.ts
+import Activity from '#models/activity'
+
+interface LogOptions {
+  type: string
+  description: string
+  userId?: number | null
+  subjectType?: string | null
+  subjectId?: number | string | null
+  properties?: Record<string, any>
+}
+
+export default class ActivityLogger {
+  static async log(options: LogOptions): Promise<void> {
+    await Activity.create({
+      type: options.type,
+      description: options.description,
+      userId: options.userId ?? null,
+      subjectType: options.subjectType ?? null,
+      subjectId: options.subjectId != null ? Number(options.subjectId) : null,
+      properties: options.properties ?? null,
+    })
+
+    // Invalidate the cache if you add one (see Redis section).
+    // await redis.del('activities:recent')
+  }
+}