[Bug]: GitLab overview discussions are never review findings, so they get no Fix button #30396

Area

Pull requests (GitLab provider)

Steps to reproduce

1. On a GitLab merge request, start a thread from the Overview tab ("Start a thread", not a plain comment), and leave it unresolved. TonybynMp4/git-ansible!5 has one: "Overview finding: the README should mention these fixtures."
2. Open that merge request in T3 Code and look at the Summary tab's comments.

Expected behavior

An unresolved overview thread is a finding, like a thread on a diff line. It gets "Fix in a thread", and "Fix findings" includes it.

Actual behavior

It shows as a plain comment with no Fix button, and "Fix findings" leaves it out. Diff threads on the same MR do get the button.

The adapter builds comments from /notes, which can't tell an overview thread's first note from its replies, or from a resolved one. /discussions can:

$ glab api "projects/TonybynMp4%2Fgit-ansible/merge_requests/5/notes?sort=asc"   (non-system notes)
{"id":4154544846,"type":null,"resolvable":false,"resolved":null,"position":false,"body":"Plain overview comment: looks fine to me."}
{"id":4154544931,"type":"DiscussionNote","resolvable":true,"resolved":false,"position":false,"body":"Overview finding: the README should mention t"}
...
{"id":4154730801,"type":"DiscussionNote","resolvable":true,"resolved":false,"position":false,"body":"Reply: agreed, will update the README."}

$ glab api "projects/TonybynMp4%2Fgit-ansible/merge_requests/5/discussions"   (non-system)
{"id":"07d2d498","individual_note":true,"position":false,"notes":[{"id":4154544846,"resolvable":false,"resolved":null}]}
{"id":"957dc728","individual_note":false,"position":false,"notes":[{"id":4154544931,"resolvable":true,"resolved":false},{"id":4154730801,"resolvable":true,"resolved":false}]}
...

Impact

Review feedback left on the MR as a whole, which is common for summary reviews and for bots that don't anchor to a line, can't be handed to an agent from T3 Code.

Version or commit

a10490937d (main)

Environment

Linux, web dev build, gitlab.com through glab.

Screenshots, recordings, or supporting files

On main, the overview finding has no Fix button while the diff threads do:

Workaround

Copy the comment into a thread by hand.