chore: adding hello vercel example app

[joker23]

This PR will create a hello app for vercel sdk that follow the example app specs.

This example should be much simplier and easier to follow than the existing samples.

NOTE: I am also planning on updating the existing examples in future PRs to modernize the implementation.

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Note

Low Risk
Primarily adds a new example workspace and metadata wiring; no changes to core SDK runtime behavior or production code paths.

Overview
Adds a new packages/sdk/vercel/examples/hello-vercel console example app (TypeScript build, .env.example, README) that initializes @launchdarkly/vercel-server-sdk with Vercel Edge Config, evaluates a boolean flag, and optionally polls for changes.

Registers the new example as a Yarn workspace, updates release-please-config.json to keep the example’s SDK dependency in sync, and renames the React Vercel Edge example package from @internal/... to @launchdarkly/....

^{Reviewed by Cursor Bugbot for commit c42eb49. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

@launchdarkly/js-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 25623 bytes
Compressed size limit: 29000
Uncompressed size: 125843 bytes

[github-actions]

@launchdarkly/js-client-sdk size report
This is the brotli compressed size of the ESM build.
Compressed size: 31664 bytes
Compressed size limit: 34000
Uncompressed size: 112917 bytes

[github-actions]

@launchdarkly/browser size report
This is the brotli compressed size of the ESM build.
Compressed size: 179382 bytes
Compressed size limit: 200000
Uncompressed size: 830105 bytes

[github-actions]

@launchdarkly/js-client-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 37214 bytes
Compressed size limit: 38000
Uncompressed size: 204443 bytes

[joker23]

@cursor review

[cursor]

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 3 additional findings.