Introduces a new opcounters.aggregates metric that tracks top-level aggregate command invocations as their own exclusive counter, replacing the previous behavior where aggregate incremented opcounters.queries. The two counters are now fully mutually exclusive: an aggregate call increments only aggregates, and a find call increments only queries. Neither increments opcounters.commands.

Description of Linked Ticket

Overview

Introduce a new opcounters.aggregate metric to track top-level aggregate commands separately from the general command counter.

Scope of Work

• src/mongo/db/stats/opcounters.h/.cpp — Add gotAggregate() method and aggregate counter field
• Shard role service entry point and mongos strategy — Call gotAggregate() when processing aggregate commands

Technical Notes

• appears in OTel output, and also in serverStatus.opcounters