implemented test suite

[y-aithnini]

Summary

• What does this PR change?

Why

• Why is this change needed?

Checklist

• Added/updated tests (if behavior changed)
• npm run lint passes
• npm run typecheck passes
• npm test passes
• npm run build passes
• Added a changeset (npx changeset) if this affects consumers

Notes

• Anything reviewers should pay attention to?

[Copilot]

Pull request overview

Adds an initial Jest test suite for the core ConfigKit APIs and tightens Jest coverage thresholds.

Changes:

• Added unit tests for defineConfig() / ConfigDefinition.parse() and ConfigValidationError.
• Added unit + integration tests for defineNamespace(), NamespacedConfig.asProvider(), DuplicateNamespaceError, and @InjectConfig().
• Added integration tests for ConfigModule registration modes and increased global Jest coverage thresholds to 85%.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
src/errors/config-validation.error.spec.ts	Unit tests for ConfigValidationError formatting/identity behavior.
src/define-namespace.spec.ts	Tests namespace definition, provider factory behavior, and DI integration via @InjectConfig().
src/define-config.spec.ts	Tests defineConfig() and parse() behavior across success/failure cases.
src/config.module.spec.ts	NestJS integration tests for ConfigModule/ConfigService registration paths.
jest.config.ts	Raises global coverage thresholds from 80% to 85%.