fix: Add support for graph metric tracking

[jsonbailey]

Summary

• Introduces LDGraphTracker interface and LDGraphTrackerImpl for tracking graph-level and edge-level metrics in AI agent graph operations
• Extends LDAIConfigTracker with optional graphKey parameter on all tracking methods, enabling node-level events to carry graph context
• Adds trackToolCall / trackToolCalls methods to LDAIConfigTracker
• Implements at-most-once semantics for graph-level metrics (invocation success/failure, latency, total tokens, path); edge-level methods (redirect, handoff) are multi-fire

Changes

New LDGraphTracker interface (src/api/graph/LDGraphTracker.ts):

• Graph-level: trackInvocationSuccess, trackInvocationFailure, trackLatency, trackTotalTokens, trackPath, trackJudgeResponse
• Edge-level: trackRedirect, trackHandoffSuccess, trackHandoffFailure
• getSummary() returning LDGraphMetricSummary

Updated LDAIConfigTracker interface:

• All tracking methods accept an optional graphKey?: string parameter
• New trackToolCall(toolKey, graphKey?) and trackToolCalls(toolKeys, graphKey?) methods
• getTrackData(graphKey?) includes graphKey in the payload when provided

Spec references: AIGRAPHTRACK, AITRACK
Python reference: python-server-sdk-ai main

Test plan

• All 125 existing + new tests pass (yarn workspace @launchdarkly/server-sdk-ai test)
• Lint clean (yarn workspace @launchdarkly/server-sdk-ai lint)
• New LDGraphTrackerImpl.test.ts covers all graph tracking methods, at-most-once semantics, and edge-level multi-fire behavior

🤖 Generated with Claude Code

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Note

Medium Risk
Expands the public tracking API (LDAIConfigTracker) and introduces new tracking events, which could affect downstream consumers and event volume/shape if adopted; changes are contained to metrics/tracking code paths.

Overview
Adds first-class agent graph metric tracking via a new LDGraphTracker API and LDGraphTrackerImpl, emitting graph-level events (invocation success/failure, latency, total tokens, path, judge evals) plus edge events (redirects and handoffs) and exposing a getSummary() of captured graph metrics.

Extends LDAIConfigTracker/LDAIConfigTrackerImpl so all existing tracking methods accept an optional graphKey and include it in event payloads when provided, and adds new trackToolCall/trackToolCalls methods that emit $ld:ai:tool_call events.

Exports the new graph API from src/api and re-exports LDGraphTrackerImpl from the package entrypoint, with comprehensive new/updated unit tests covering graphKey propagation, tool-call tracking, and at-most-once semantics for graph-level metrics.

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[github-actions]

@launchdarkly/js-client-sdk-common size report
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[joker23]

JS looks good - will await @andrewklatzke's review