Release Plan: Support patch releases for single-SDK fixes

Background / problem

The Release Plan data model currently assumes a full release scope, where release planning often involves service/API changes and coordination across multiple language SDKs. Some releases are narrower patch releases that only contain SDK-related work for a single language SDK.

Note: this is about the Release Plan data model — not the Release Planner web app, which is being sunset.

Proposed behavior

Update the Release Plan to represent a release scoped to a single library and language SDK patch when no service/API changes or multi-language coordination are required. The Release Plan should support tracking these targeted releases without requiring the full release workflow.

Example use case

A bug is fixed in one Python SDK package and needs a patch release for that package only. The Release Plan should represent and track this as a single-library Python SDK patch, without requiring other language SDKs or service/API release steps.

Open questions

• What versioning rules should apply for single-SDK patch releases?
• What approval flow is required for targeted SDK-only patches?
• Which release artifacts or notifications should be required for this scope?

Start by tracing the Release Plan data model and comparing its full-release assumptions with the single-library Python SDK patch scenario. The work is done when versioning, approval flow, required artifacts, and notifications are defined and the model can track a targeted SDK-only release without the full workflow.