[Fix] Linear issue comments fail when tasks use issue updates

[roomote-roomote]

​Opened on behalf of @mrubens. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

Linear-backed tasks now receive explicit mutation guidance that keeps issue comments on Linear's dedicated comment tool and reserves issue-update tools for fields such as status, title, description, assignee, and labels. The guidance also requires agents to surface the actual Linear tool error instead of inventing a different diagnosis.

Regression coverage verifies both the integration catalog guidance and its injection into OpenCode task runtimes when Linear is attached.

Why this change was made

Agents could attempt to add issue discussion through an issue or status update tool, causing the request to be rejected and producing misleading failure explanations.

Impact

Requests to add discussion to a Linear issue are directed to the correct tool, while genuine Linear errors are reported accurately. Existing Linear authentication, routing, and issue-field updates are unchanged.

[roomote-community]

No code issues found. See task

_{Reviewed 1df416b}