Add outgoing message count report endpoint grouped by agent, team, inbox, or label

Add outgoing message count report endpoint grouped by agent, team, inbox, or label: a task in bird-critic-1.5-full-300 (Harbor dataset). Chatwoot's v2 reports API needs a new analytics endpoint that returns per-entity counts of outgoing messages within a date range. This allows account…

The task

Chatwoot's v2 reports API needs a new analytics endpoint that returns per-entity counts of outgoing messages within a date range. This allows account administrators to measure agent and team output without exporting raw message data.

Part of kochsnow/bird-critic-1.5-full-300.