feat: allow to combine overrides

[nfroidure]

fix #143

[Copilot]

Pull request overview

This PR implements support for nested $overrides using a __self key so a service can be overridden while still allowing overrides for its dependencies (addressing issue #143). It also reserves the __self service name to avoid collisions with the new override syntax.

Changes:

• Extend override resolution to support nested override maps containing __self, including dependency overrides for the overridden target.
• Prevent registering a service named __self and add a dedicated error code for that case.
• Add test coverage for the new override behavior and the reserved-name guard.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/overrides.ts	Adds __self support to the override lookup logic and updates the Overrides type.
src/overrides.test.ts	Adds unit tests for nested __self overrides and dependency override lookup.
src/index.ts	Rejects registration of the reserved service name __self.
src/index.test.ts	Adds integration tests for reserved name rejection and nested __self overrides end-to-end.
src/errors.ts	Registers the new E_RESERVED_SERVICE_NAME error type for TypeScript consumers.
README.md	Updates an import in the usage example (currently introduces a mismatch with the rest of the snippet).
ARCHITECTURE.md	Updates an internal “See in context” line-number link.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.