Propagate errors in register_github_issue_routine instead of panicking

[coderabbitai]

Background

Raised during review of PR #116 by @leynos.

register_github_issue_routine in tests/support/routines.rs currently panics on database error via .expect("create_routine"). It should propagate errors to callers instead.

Required changes

1. Update the function signature in tests/support/routines.rs

Change the signature from:

pub async fn register_github_issue_routine(
    db: &Arc<dyn Database>,
    engine: &RoutineEngine,
) -> Routine

to:

pub async fn register_github_issue_routine(
    db: &Arc<dyn Database>,
    engine: &RoutineEngine,
) -> Result<Routine, Box<dyn std::error::Error>>

Replace:

db.create_routine(&routine).await.expect("create_routine");

with:

db.create_routine(&routine).await?;

and return Ok(routine) at the end.

2. Update all call-sites

Update all callers of register_github_issue_routine (e.g. in tests/e2e_traces/routine_system_event.rs) to propagate the error using ? or .expect() inside the #[tokio::test] function body. (.expect() is permitted inside #[test]-attributed functions.)

Acceptance criteria

• register_github_issue_routine returns Result<Routine, Box<dyn std::error::Error>>.
• No .expect("create_routine") remains inside the helper function body.
• All call-sites handle the Result appropriately.

References

• PR: Refactor: split routine_heartbeat.rs into focused submodules (#25) #116
• Comment: Refactor: split routine_heartbeat.rs into focused submodules (#25) #116 (comment)