The activity feed and since-last-check inbox previously filtered to
only open items via state = 'opened' checks in the SQL subqueries.
This meant comments on merged MRs (post-merge follow-ups, questions)
and closed issues were silently dropped from the feed.
Remove the state filter from the association checks in both
query_activity() and query_since_last_check(). The user-association
checks (assigned, authored, reviewing) remain — activity still only
appears for items the user is connected to, regardless of state.
The simplified subqueries also eliminate unnecessary JOINs to the
issues/merge_requests tables that were only needed for the state
check, resulting in slightly more efficient index-only scans on
issue_assignees and mr_reviewers.
Add 4 tests covering: merged MR (authored), closed MR (reviewer),
closed issue (assignee), and merged MR in the since-last-check inbox.
62fbd7275e