Bump cluster-ui Version

Automate the two cluster-ui version bumps required after a release branch is created. This creates two PRs:

1. Release branch PR: Drop the prerelease suffix (e.g., 26.2.0-prerelease.0 → 26.2.0)
2. Master PR: Increment minor version for next cycle (e.g., 26.2.0-prerelease.0 → 26.3.0-prerelease.0)

The file to edit is pkg/ui/workspaces/cluster-ui/package.json (the "version" field).

Workflow

Step 1: Gather Inputs

Ask the user for:

1. Release version (required) — e.g., 26.2. This is the version that was just branched.
2. Jira epic (optional) — e.g., REL-4280. Included in commit messages if provided.

Step 2: Validate