Building sequences after running expansion rules doesn't populate `expanded_sequences`

Checked for duplicates

Yes - I've already checked

Is this a regression?

No - This is a new bug

Version

develop

Describe the bug

#899 introduced the expanded_sequences table, which gets populated when you first define your sequences and then run expansion. It does not, however, get populated if you define your sequences after running expansion. This gets complicated because the UI pulls from expanded_sequences on the expansion runs page, but pulls from a separate route that generates the sequences on the fly (and so doesn't surface this bug) when viewing the expanded sequence from the plan.

Reproduction

• Simulate a plan
• Run expansion
• Link activities to sequences
• View the sequence from the Plan and see it exists
• View the sequence from "AERIE" menu > "Expansion" > "Runs" and see it is blank

Logs

System Info

local dep

Severity

Moderate

Trace the Expansion > Runs page's use of the expanded_sequences table alongside the Plan sequence view's on-the-fly route, starting with the sequence creation and expansion flow in the reproduction. Confirm that defining sequences after expansion still makes them appear in both views, regardless of operation order.