NethVoice CTI: Group calls in call history (expandable interactions)

[tommaso-ascani]

Description:
In Call History a single logical call often produces several CDR legs sharing one linkedid (a queue/group call ringing multiple members, transfers, consultation legs). Today these appear as separate rows. This feature collapses them into one parent row per call, expandable to reveal all its interactions, across the Personal / Switchboard / Groups views.

Design reference: Figma "History: Group calls" / PdR-to-design #7371.

Behavior:

• Parent row = the answered leg; a stacked-layers icon + tooltip mark calls with multiple interactions.
• A caret toggles expansion, revealing the interaction sub-rows (date, destination, duration, outcome).

Test Case:

1. Place a queue call ringing several agents; one answers.
2. Open Call History (Personal / Switchboard / Groups view).
3. The call shows the multiple-interactions icon and an expand caret.
4. Expand it → the other legs (missed rings, transfers) appear as indented sub-rows.

Grouping by linkedid is implemented in nethcti-middleware; the UI in nethvoice-cti.