chore(deps): bump @opentelemetry deps to v2.x

[JoshElias]

Description

Update OpenTelemetry dependencies to v2.x and adapt code to the breaking API changes.

Summary

• Update @opentelemetry/sdk-metrics from v1.x to v2.x
• Update @opentelemetry/core to v2.x
• Migrate from class-based aggregations to object-based AggregationOption API
• Replace MeterProvider.addMetricReader() with constructor-based reader registration
• Update test fixtures and examples to use v2.x API
• Update documentation to reflect new API usage

Breaking Changes in OTel v2.x Addressed

1. MeterProvider.addMetricReader() removed - Now pass readers via constructor options
2. Aggregation classes removed (SumAggregation, LastValueAggregation, etc.) - Now use object-based { type: AggregationType.SUM } format
3. Minimum Node.js version raised to ^18.19.0 || >=20.6.0 in OTel SDK

Checklist

• Implement code
  - [ ] Add tests
  - [ ] Update TypeScript typings
• Update documentation
  - [ ] Add release notes to docs/release-notes/index.md
• Commit message follows commit guidelines

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🔍 Preview links for changed docs

• docs/reference/opentelemetry-bridge.md

[JoshElias]

❌ Author of the following commits did not sign a Contributor Agreement: 25a8bdf, 129899d, 274e44e

Please, read and sign the above mentioned agreement if you want to contribute to this project

I have since signed this.

[JoshElias]

Happy to make any required changes to fit your standards!

[JoshElias]

I just noticed that my auto formatter was a bit aggressive in the .md and .js files. I'll clean that noise out.