fix: add .js extensions to ESM exports for Node.js resolution

[wcole1-godaddy]

Problem

The ESM build at dist/esm/index.js exports without .js extensions:

export * from './src/extensions';
export * from './src/spec_generated';

This causes Node.js ESM resolution to fail with errors like:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module './src/extensions'

Solution

Add explicit .js extensions to all ESM import/export paths. TypeScript preserves these extensions in the compiled output, allowing Node.js ESM to resolve modules correctly.

Changes

• index.ts: Added .js extension to exports
• src/extensions.ts: Added .js extension to spec_generated import

Testing

After this fix, ESM imports work correctly:

node --input-type=module -e "import * as sdk from './dist/esm/index.js'; console.log(Object.keys(sdk).length);"

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