[FFL-2926] Add tracking parity to DatadogOfflineProvider

[sameerank]

Summary

• add optional browser telemetry configuration to DatadogOfflineProvider
• reuse the existing DatadogProvider exposure, flag-evaluation, and RUM tracking hooks through shared setup
• keep offline evaluation telemetry-free when tracking is omitted
• keep configuration delivery through setConfiguration(), consistent with React Native
• attribute telemetry to the actual effective OpenFeature context used for evaluation
• support the same tracking behavior for precomputed and rules-based offline evaluation
• reset exposure deduplication when setConfiguration replaces the active configuration
• prevent asynchronous persistent-cache initialization from restoring stale deduplication entries after replacement
• keep offline configuration delivery free of fetching and polling even when telemetry is enabled

Why

Offline describes configuration delivery, not necessarily telemetry. Consumers should be able to opt into the same browser tracking behavior as DatadogProvider without introducing configuration fetching or polling.

When tracking is omitted, DatadogOfflineProvider remains evaluation-only and creates no tracking hooks or telemetry requests. The constructor accepts only optional browser tracking settings; caller-supplied flag configuration is loaded separately with setConfiguration().

Jira: FFL-2926

Behavior and compatibility

• supplying a tracking block enables exposure, flag-evaluation, and RUM tracking with the same defaults and hook order as DatadogProvider
• each integration can be disabled independently
• context-specific precomputed consumers must register the matching context; {} is treated literally
• tracking hooks observe the same OpenFeature context used for evaluation
• successful precomputed and rules evaluations carry existing allocation, variation, context, logging, and timestamp metadata
• defaults and failed evaluations do not emit exposure events
• tracking failures do not affect local evaluation or provider lifecycle
• the existing DatadogProvider constructor, fetching, caching, and tracking behavior remain unchanged

Stack and merge order

This PR is stacked on #346, which documents static initialization with getPrecomputedContext and treats empty OpenFeature contexts literally.

1. Merge #344.
2. Merge #353.
3. Retarget and merge #336.
4. Retarget and merge #346.
5. Retarget this PR to main and merge it.

Validation

• full browser suite passed: 18 suites and 203 tests
• monorepo build and TypeScript checks passed
• Biome checks passed