[BUG] Imported recurring task instances don't inherit categories from the parent task

[josesantosdigital]

Describe the bug

Imported recurring tasks correctly retain their assigned categories on the parent task, and those categories are visible when editing it.

However, the generated recurring task instances (the TODOs displayed in the task list) do not appear to inherit those categories. As a result, category filters do not match imported recurring tasks.

Recurring tasks created directly in jtx Board do not exhibit this behavior: their generated task instances are correctly associated with the assigned categories, and category filters work as expected.

Imported non-recurring tasks also work correctly with category filters.

---

To Reproduce

1. Create a new task calendar in jtx Board (or use an existing one).
2. Import an ICS file containing recurring VTODOs with CATEGORIES and an RRULE.
3. Sync/import successfully.
4. Open the category filter and select one of the imported categories (e.g. Kitchen).

Example VTODO

BEGIN:VTODO
SUMMARY:Kitchen · Clean
CATEGORIES:Kitchen,Clean,Daily
DTSTART;VALUE=DATE:20260707
RRULE:FREQ=DAILY
END:VTODO

---

Observed behavior

• The imported recurring task shows the correct categories when opened.
• The recurring task itself appears to have the categories assigned.
• Filtering by any of those categories does not display the recurring task.
• Imported non-recurring tasks filter correctly.
• Recurring tasks created manually inside jtx Board also filter correctly.

I also exported a recurring task that was originally created in jtx Board, deleted it, and re-imported the exported ICS. After importing, the recurring task no longer matched category filters, even though it was originally created by jtx Board.

This suggests the issue is related to the ICS import process rather than the ICS format itself.

---

Expected behavior

Recurring tasks imported from a valid ICS file should behave identically to recurring tasks created inside jtx Board.

If a recurring task has one or more categories assigned, filtering by those categories should include the task.

---

Additional information

During testing it appears that the master recurring task retains its categories after import, but the generated occurrences used by the UI do not participate in category filtering. This may indicate that categories are not propagated (or not indexed) for recurring instances created during import.

I can provide a minimal reproducible ICS file if needed.