Compute rebalance plan

curl --request POST \
  --url https://backend.inkwell.finance/api/v1/ika/agent/rebalance-plan \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "positions": [
    {
      "stakedIkaId": "<string>",
      "validatorId": "<string>",
      "principal": "<string>"
    }
  ],
  "maxTargets": 10
}
'

{
  "currentPositions": [
    {
      "validator": "<string>",
      "stakedAmount": "<string>",
      "currentApy": 123
    }
  ],
  "steps": [
    {
      "action": "unstake",
      "validator": "<string>",
      "amount": "<string>",
      "requiresEpochWait": true,
      "order": 123
    }
  ],
  "summary": {
    "currentWeightedApy": 123,
    "projectedWeightedApy": 123,
    "estimatedEpochsToComplete": 123
  },
  "dataAgeSeconds": 123
}