fix(create-blocks-app): include Amplify dev server template

[ikenyal]

Problem

Issue #, if available: Fixes #241

When AWS Blocks is added to an Amplify Gen 2 project, the CLI adds blocks:dev with tsx watch aws-blocks/scripts/server.ts. The Amplify overlay did not include that file, so the documented command immediately failed with ERR_MODULE_NOT_FOUND.

This is present in the published @aws-blocks/create-blocks-app package as well as in the repository source.

Changes

• Add the missing Amplify aws-blocks/scripts/server.ts template, using the existing backend-template local server pattern on port 3001.
• Extend the Amplify auto-detection test to verify that the generated blocks:dev script has a matching server file.
• Add a patch changeset for @aws-blocks/create-blocks-app.

Validation

• Added a regression assertion that failed before the template was added and passes after the fix.
• npm run build
• npm run lint:deps
• npm test
• npm run test:e2e:local (comprehensive: 372 passed, 0 failed, 1 skipped; vendorize: 8 passed, 0 failed)
• npm pack --dry-run --workspace @aws-blocks/create-blocks-app confirms the new template is included.
• npx changeset status

Checklist

• PR description included
• Tests are changed or added
• Relevant documentation is changed or added (not applicable: this restores the already-generated blocks:dev command; it adds no new user-facing workflow or API documentation.)

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[changeset-bot]

🦋 Changeset detected

Latest commit: d0bb476

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/create-blocks-app	Patch

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