Release planner: Auto update change log and release management plane SDK

Support auto release of SDK when SDK PR is merged when service provides:
- Confirm that service is ready to release
- Provide a release date.

**SDK agent side changes:**
When user requests to release an SDK for management plane:
Agent should prompt for the following:
1. Package name
2. Language
3. Release date
4. Is Service ready?

Agent should check if change log contains the release date and if it matches. If change log does not contains a release date, create a PR to update the change log. If change log already contains the release date then it should run release pipeline.

**Engsys pipeline side changes:**
Automated release step:
One solution is to kick off the SDK release stage automatically by CI pipeline on the merge of change log with a release date that matches current date and if there is an active release plan for that package.

No files, tests, or entry points are named. Start by mapping the SDK agent’s release-request flow and the Engsys pipeline release stage described here; done means the required release details are collected, change-log dates are checked, and matching active release plans can trigger automation.

Written by the indexing model from the issue text.