chore(evaluation-context): Add feature metadata

[khvn26]

Thanks for submitting a PR! Please check the boxes below:

• I have added information to docs/ if required so people know about the feature!
• I have filled in the "Changes" section below?
• I have filled in the "How did you test this code" section below?
• I have used a Conventional Commit title for this Pull Request

Changes

In this PR, we add feature metadata to contain implementation-specific feature attributes.

How did you test this code?

N/A

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3 Skipped Deployments

Project	Deployment	Preview	Comments	Updated (UTC)
docs	Ignored			Oct 16, 2025 11:28am
flagsmith-frontend-preview	Ignored			Oct 16, 2025 11:28am
flagsmith-frontend-staging	Ignored			Oct 16, 2025 11:28am

[github-actions]

Docker builds report

Image	Build Status	Security report
ghcr.io/flagsmith/flagsmith-api-test:pr-6166	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-e2e:pr-6166	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-frontend:pr-6166	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-api:pr-6166	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith:pr-6166	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-private-cloud:pr-6166	Finished ✅	Results ✅