Include unit and type for metrics descriptions in mcp/metadata/ontap_metrics.json

[gautcher]

Is your feature request related to a problem? Please describe.

Some of the ONTAP metrics in the mcp/metadata/ontap_metrics.json file are missing their units, and it is confusing my AI agent that uses the tool when asking for the metric description. Some of the metrics do have a unit, but only because it is mentioned in the textual description of the metric.

Here are two examples:

https://github.com/NetApp/harvest/blob/main/mcp/metadata/ontap_metrics.json#L1391

https://github.com/NetApp/harvest/blob/main/mcp/metadata/ontap_metrics.json#L1514

Describe the solution you'd like
Include the type and unit of each metric as shown here:

https://netapp.github.io/harvest/latest/ontap-metrics/#svm_vol_write_latency

Describe alternatives you've considered
I have to explain in the agent prompt which metric names are milliseconds and which are microseconds.