Agent Skills: lisa-linear-evidence

Uploads text evidence to the GitHub `pr-assets` release, updates the PR description, posts a comment on the originating Linear Issue with code blocks, and transitions the Issue from the configured `claimed` workflow state to the configured `review` workflow state. Reusable by any skill that captures evidence and generates evidence/comment.txt + evidence/code-blocks.md. Linear counterpart of lisa-jira-evidence and lisa-github-evidence.