feat: Add public analytics-metadata entry point

[saipavan-narasaraj]

Summary

Adds a public @cloudscape-design/component-toolkit/analytics-metadata entry
point (and .../analytics-metadata/utils) exposing the analytics metadata API
that today is only reachable via internal/analytics-metadata.

Component libraries built on top of Cloudscape instrument their own components
with this mechanism, alongside the metadata Cloudscape components emit, so that
one extraction returns a single consistent hierarchy. Because the entry points
live under internal/ with no stability commitment, such a library has to
redefine the types in a wrapper package to avoid leaking an internal path into
its own public API, and re-verify the surface on every toolkit release. With a
public path those redefinitions become plain re-exports.

The functions are already published in the package's exports map, so this is
closer to documenting existing surface than adding new API.

Changes

• New src/analytics-metadata/index.ts re-exporting activateAnalyticsMetadata,
  getAnalyticsMetadataAttribute and the types GeneratedAnalyticsMetadata,
  GeneratedAnalyticsMetadataFragment, LabelIdentifier.
• New src/analytics-metadata/utils.ts re-exporting getGeneratedAnalyticsMetadata,
  getComponentsTree and the types GetComponentsTreeOptions, OptionItem, TabItem.
• exports and typesVersions entries for both paths.
• Unit test asserting the public surface, function identity with the internal
  entry point, and shared activation state.

Kept as two paths rather than one so component-runtime consumers of
getAnalyticsMetadataAttribute do not pull in the page-scanner and
label-extraction code.

Non-goals

• No behaviour changes. Both files are pure re-exports.
• internal/analytics-metadata and .../utils are unchanged and not deprecated.
• No new implementation. The activation flag is module-level state, so a second
  copy would silently split it; re-exporting keeps one instance.
• No version bump or changelog (none exists in this repo).

Testing

• npm run build — verified lib/analytics-metadata/{index,utils}.{js,d.ts} and
  lib/mjs/analytics-metadata/{index,utils}.{js,d.ts} are all emitted
• npm run lint — clean
• CI=true npm run test:unit — 52 suites / 491 tests pass
• Runtime resolution from lib/, both formats:
  require('./analytics-metadata/index.js') and
  import('./mjs/analytics-metadata/utils.js') export the expected names
• git secrets --scan on the changed files
• Integ tests not run locally (need Chrome + chromedriver); relying on CI

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