Recall analytics and dead memory detection

curl --request GET \
  --url https://api.example.com/api/analytics/recall-stats \
  --header 'Authorization: Bearer <token>'

{
  "top_recalled": [
    {
      "id": 123,
      "topic": "<string>",
      "memory_type": "<string>",
      "recall_count": 123,
      "last_recalled_at": "2023-11-07T05:31:56Z",
      "created_at": "2023-11-07T05:31:56Z"
    }
  ],
  "never_recalled": [
    {
      "id": 123,
      "topic": "<string>",
      "memory_type": "<string>",
      "recall_count": 123,
      "last_recalled_at": "2023-11-07T05:31:56Z",
      "created_at": "2023-11-07T05:31:56Z"
    }
  ],
  "dead_memories": [
    {
      "id": 123,
      "topic": "<string>",
      "memory_type": "<string>",
      "recall_count": 123,
      "last_recalled_at": "2023-11-07T05:31:56Z",
      "created_at": "2023-11-07T05:31:56Z"
    }
  ],
  "distribution_by_type": [
    {
      "memory_type": "<string>",
      "total_recalls": 123,
      "memory_count": 123
    }
  ],
  "total_recalls_7d": 123,
  "total_recalls_30d": 123
}