bug(opportunities): Create Purchase Plan modal not prefilled when 2+ homogeneous commitments selected (QA 6.7) #898

QA finding 6.7

In Opportunities -> Plan commitments, selecting 2 or more commitments that share the SAME Provider/Service/Term/Payment and clicking "Plan from X selected" opens the Create Purchase Plan modal showing DEFAULTS (AWS, EC2, 1 Year, No Upfront) instead of prefilling from the selected commitments.

Context

PR #770/#778 already prefills the modal correctly for a SINGLE selected commitment (the prefill runs only when the selection snapshot length === 1). This issue extends that behavior to the homogeneous multi-selection case.

When 2+ commitments are selected and all share the same provider/service/term/payment (already enforced by #769/#777's homogeneity gate on the button), the modal should prefill from the common values, using the first commitment as the representative. Account can be the common account or left to multi if they differ.

Expected

Selecting 2+ homogeneous commitments and clicking "Plan from X selected" prefills provider/service/term/payment from the shared values.

Actual

Modal opens with defaults (AWS, EC2, 1 Year, No Upfront).