chore: rename trackLatency to trackDuration on LDGraphTracker

[jsonbailey]

Summary

• Renames trackLatency() → trackDuration() on the LDGraphTracker interface and LDGraphTrackerImpl class to align with the existing trackDuration naming on LDAIConfigTracker
• Updates the event key from $ld:ai:graph:latency to $ld:ai:graph:duration:total per the updated AIGRAPHTRACK spec
• Updates all tests to match the new method name and event key

Test plan

• All 144 unit tests pass (yarn workspace @launchdarkly/server-sdk-ai test)
• Lint passes clean
• Build succeeds

🤖 Generated with Claude Code

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Note

Medium Risk
This is a public API rename and event-key change that can break downstream consumers and dashboards if they still call trackLatency or rely on the old $ld:ai:graph:latency metric name.

Overview
Renames the LDGraphTracker API from trackLatency() to trackDuration() and updates LDGraphTrackerImpl and unit tests accordingly.

Changes the emitted metric event key from $ld:ai:graph:latency to $ld:ai:graph:duration:total while preserving the existing at-most-once semantics and summary reporting via durationMs.

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[github-actions]

@launchdarkly/js-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 25623 bytes
Compressed size limit: 29000
Uncompressed size: 125843 bytes

[github-actions]

@launchdarkly/js-client-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 37169 bytes
Compressed size limit: 38000
Uncompressed size: 204305 bytes

[github-actions]

@launchdarkly/browser size report
This is the brotli compressed size of the ESM build.
Compressed size: 179375 bytes
Compressed size limit: 200000
Uncompressed size: 829982 bytes

[github-actions]

@launchdarkly/js-client-sdk size report
This is the brotli compressed size of the ESM build.
Compressed size: 31655 bytes
Compressed size limit: 34000
Uncompressed size: 112792 bytes

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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