[Due for payment 2025-09-02] [Suggested Search v2.6] [App] Implement new grouping header for Reconciliation

[JS00001]

Implement this section of the design doc: https://docs.google.com/document/d/1vXMf1oK3J8A7EcjTGSPtpT2rgHWqcAg-FbuXlObjHZ4/edit?tab=t.0#bookmark=kix.a7o01cdl79dp

Issue Owner

Current Issue Owner: @adelekennedy

[JS00001]

We aren't prioritizing these yet, we are focused on release 2, 3, and 4