Fix commerce module boundaries and failing architecture test

[fdaei]

Fix commerce module boundaries and failing architecture test

Exported PackagesService from the apps/api/src/modules/commerce/index.ts barrel file and updated the architecture.spec.ts to expect it. Updated courses.service.ts to import PackagesService from the public interface instead of reaching into the internal implementation.

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PR created automatically by Jules for task 1508071049950797947 started by @fdaei

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