feat(linear): Post comment on parent issue when state changes

[rgibert]

When Firetower changes the parent Linear ticket's workflow state (via _update_parent_issue_status()), it now posts a comment explaining why the transition happened -- e.g., "Firetower set this issue to Completed. Incident INC-2001 is Done and all 3 action item(s) are complete."

This gives visibility into automated state changes directly in Linear, so people looking at the ticket understand why it moved without needing to check Firetower.

Comments are only posted after a successful update_issue() call. Template rendering errors and API failures are logged but do not block the state change.

Agent transcript: https://claudescope.sentry.dev/share/pzP9lcJ0H-hmoz7k_UeCk-Poj0JBO-AJkfGFWzMo0b0

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

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[cursor]

Same-type state skips update

Medium Severity

The early return treats the parent as already in the desired workflow when state_type equals target_state, but Linear allows several distinct workflow states that share the same type. Firetower still resolves a single state_id per type, so the parent can remain on a different “started” (or “completed”) state and never receive update_issue or a status comment.

 

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