[FEATURE] adding support for effort tracking via OTEL

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

We are utilzing the otel collected usage metrics quite heavily for cost optimasation.
However, as of today, effortis not beeing tracked. This would be really helpfull !

Proposed Solution

Adding a new effort attribute as standard attribute. Much like Model identifier oder type
https://code.claude.com/docs/en/monitoring-usage#standard-attributes

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

Configuration and settings

Use Case Example

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Additional Context

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