[codex] Add OpenTelemetry IPFS retrieval instrumentation

[0xSwego]

Summary

Adds passive OpenTelemetry API instrumentation to the JavaScript client IPFS/Zarr open path, mirroring the Python client instrumentation where this repository owns the behavior.

• Adds @opentelemetry/api as a runtime dependency without adding exporters or SDK setup.
• Wraps openDatasetFromCid with spans for dataset opens and Jaxray IPFS store opens.
• Records counters/histograms for dataset and store open requests/durations with gateway, store type, and status attributes.
• Keeps CID on trace spans only, avoiding high-cardinality metric labels.
• Documents the emitted span/metric names and adds focused tests for the open path and helper behavior.

Notes

The JS client delegates HAMT/block traversal and lower-level IPFS/Zarr behavior to @dclimate/jaxray, which is already at the latest published version (0.6.8). Those lower-level Python py-hamt counters do not have an owned equivalent in this repo.

Validation

• npm run build
• npx vitest run tests/open-dataset.test.ts
• npm test -- --run

[0xSwego]

Validation note: local JS validation passed with:

• npm run build
• npx vitest run tests/open-dataset.test.ts
• npm test -- --run

The GitHub Client Sync Check failed before reaching JS install/build/test. It fails while checking out private dClimate/dclimate-client-py from this public repo using the default Actions token:

fatal: repository 'https://github.com/dClimate/dclimate-client-py/' not found

This appears to be an existing workflow access/configuration issue rather than a failure introduced by this branch; recent main runs show the same workflow failing.