Support targeting context accessor

[zhiyuanliang-ms]

Why this PR?

#55

Support targeting context accessor pattern, align with other FM libraries

Usage

An example application can be found #105

const featureManager = new FeatureManager(provider, {targetingContextAccessor: () => ({ userId: "xxx", groups: [] }) });

If targeting context is explicitly provided within isEnabled or getVariant call, it will have the higher priority than the targeting context accessor. See the testcases and comment

[Copilot]

Copilot reviewed 5 out of 7 changed files in this pull request and generated no comments.

Files not reviewed (2)

• src/feature-management/package-lock.json: Language not supported
• src/feature-management/src/filter/TargetingFilter.ts: Evaluated as low risk

[zhiyuanliang-ms]

Example are added in #105