Fix getCallerBaggagePairs: resolve userId across all channels

[PengF (fpfp100)]

Summary

• Port of Fix GetCallerBaggagePairs: resolve userId across all channels Agent365-dotnet#246
• userId baggage was only set from aadObjectId, which is undefined on non-Teams channels and A2A calls
• Added fallback chain: aadObjectId → agenticUserId → from.id

Channel behavior after fix

Field	Teams	Other channels (aadObjectId null)	A2A (user)	A2A (agent)
userId	aadObjectId	from.id	aadObjectId	agenticUserId

Test plan

• Existing tests pass
• New test: non-Teams channel — userId falls back to from.id
• New test: A2A — userId falls back to agenticUserId
• New test: precedence — aadObjectId wins when all set

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes caller userId OpenTelemetry baggage population in the observability hosting utilities so that user.id is resolved consistently when aadObjectId is missing (e.g., non-Teams channels and A2A scenarios). It aligns the Node implementation with the referenced .NET behavior and adds test coverage for the new precedence rules.

Changes:

• Update getCallerBaggagePairs to resolve userId via aadObjectId → agenticUserId → from.id.
• Add/adjust unit tests to cover non-Teams fallback, A2A fallback, and precedence when all fields are present.
• Add Jest module mapping for @microsoft/agents-a365-observability-hosting to ensure tests resolve local source.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
tests/observability/extension/hosting/TurnContextUtils.test.ts	Adds coverage for new userId fallback/precedence behavior in caller baggage extraction.
tests/observability/extension/hosting/BaggageBuilderUtils.test.ts	Updates expectation to reflect new caller userId baggage population via fallback chain.
tests/jest.config.cjs	Adds moduleNameMapper entry so tests can import @microsoft/agents-a365-observability-hosting from workspace source.
packages/agents-a365-observability-hosting/src/utils/TurnContextUtils.ts	Implements userId fallback chain when building caller baggage pairs.