feat(llm-observability): metric and feedback methods

[skoob13]

Problem

It should be straightforward to capture a LLM metric or feedback.

Changes

• Add methods to capture user feedback and metrics.
• Convert values like numbers and booleans to strings to unify the property type.

@k11kirky please check the naming. I thought about captureAIFeedback, but I don't like three capital letters in a row. captureFeedback and captureMetric are probably too generic.

Release info Sub-libraries affected

Bump level

• Major
• Minor
• Patch

Libraries affected

• All of them
• posthog-web
• posthog-node
• posthog-react-native

Changelog notes

• Added captureTraceMetric and captureTraceFeedback methods for LLM Observability.

[greptile-apps]

PR Summary

This PR adds new LLM observability methods to capture metrics and user feedback across all PostHog JS Lite sub-libraries, with appropriate version bumps following semantic versioning.

• Added captureTraceFeedback method in posthog-core/src/index.ts to track user feedback with $ai_feedback events
• Added captureTraceMetric method in posthog-core/src/index.ts to track metrics with $ai_metric events
• Implemented automatic string conversion for numeric/boolean values in both methods for consistent property types
• Added comprehensive test coverage in posthog-core/test/posthog.ai.spec.ts verifying feedback/metric capture and type conversions
• Bumped minor versions across all sub-libraries (posthog-node: 4.5.0, posthog-react-native: 3.7.0, posthog-web: 3.3.0)

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[github-actions]

Size Change: +539 B (+0.41%)

Total Size: 131 kB

Filename	Size	Change
posthog-react-native/lib/posthog-core/src/index.js	10.3 kB	+103 B (+1.01%)
posthog-web/lib/index.cjs.js	18.3 kB	+218 B (+1.21%)
posthog-web/lib/index.esm.js	18.2 kB	+218 B (+1.21%)

ℹ️ View Unchanged

Filename	Size
posthog-node/lib/index.cjs.js	31 kB
posthog-node/lib/index.esm.js	31 kB
posthog-react-native/lib/posthog-core/src/eventemitter.js	1.08 kB
posthog-react-native/lib/posthog-core/src/lz-string.js	1.42 kB
posthog-react-native/lib/posthog-core/src/types.js	420 B
posthog-react-native/lib/posthog-core/src/utils.js	870 B
posthog-react-native/lib/posthog-core/src/vendor/uuidv7.js	2.04 kB
posthog-react-native/lib/posthog-react-native/index.js	485 B
posthog-react-native/lib/posthog-react-native/src/autocapture.js	1.8 kB
posthog-react-native/lib/posthog-react-native/src/frameworks/wix-navigation.js	651 B
posthog-react-native/lib/posthog-react-native/src/hooks/useFeatureFlag.js	437 B
posthog-react-native/lib/posthog-react-native/src/hooks/useFeatureFlags.js	362 B
posthog-react-native/lib/posthog-react-native/src/hooks/useLifecycleTracker.js	416 B
posthog-react-native/lib/posthog-react-native/src/hooks/useNavigationTracker.js	628 B
posthog-react-native/lib/posthog-react-native/src/hooks/usePostHog.js	249 B
posthog-react-native/lib/posthog-react-native/src/legacy.js	810 B
posthog-react-native/lib/posthog-react-native/src/native-deps.js	1.31 kB
posthog-react-native/lib/posthog-react-native/src/optional/OptionalAsyncStorage.js	183 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalExpoApplication.js	215 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalExpoDevice.js	211 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalExpoFileSystem.js	224 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalExpoLocalization.js	216 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalReactNativeDeviceInfo.js	220 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalReactNativeLocalize.js	169 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalReactNativeNavigation.js	218 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalReactNativeNavigationWix.js	222 B
posthog-react-native/lib/posthog-react-native/src/optional/OptionalSessionReplay.js	231 B
posthog-react-native/lib/posthog-react-native/src/posthog-rn.js	4.42 kB
posthog-react-native/lib/posthog-react-native/src/PostHogContext.js	210 B
posthog-react-native/lib/posthog-react-native/src/PostHogProvider.js	1.57 kB
posthog-react-native/lib/posthog-react-native/src/storage.js	1.09 kB
posthog-react-native/lib/posthog-react-native/src/types.js	90 B
posthog-react-native/lib/posthog-react-native/src/version.js	123 B

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[marandaneto]

missing changelogs and the versioning might be outdated already, but otherwise LGTM

[marandaneto]

left a comment before merging, LGTM