fix(bb-distributed-data): register DSQL runtime config

[ikenyal]

Problem

DistributedDatabase registers its DSQL endpoint and region directly on the shared Blocks Lambda. Resource mappings should use the shared config registry so they do not consume the Lambda environment-variable budget.

Issue #, if available: N/A

Changes

• Register the DSQL endpoint and region through registerConfig().
• Keep the migration custom-resource Lambda environment unchanged; it is separate from the customer-facing Blocks Lambda.
• Update CDK synthesis coverage to verify the application handler receives config-registry wiring, has no direct endpoint or region variables, and the deployed config includes both values.
• Add a patch changeset for @aws-blocks/bb-distributed-data.

Validation

• npm run build --workspace @aws-blocks/bb-distributed-data
• npm test --workspace @aws-blocks/bb-distributed-data (146 passing tests)
• npm run lint:deps
• changeset status --since=origin/main

Checklist

• PR description included
• Tests are changed or added
• Relevant documentation is changed or added (not applicable: no user-facing API or workflow change)

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[changeset-bot]

🦋 Changeset detected

Latest commit: 64d725e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@aws-blocks/bb-distributed-data	Patch

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