Increased coverage thresholds to 90% across all metrics. Added exclusions for `.spec.ts` and `.test.ts` files to the coverage configuration. Introduced new test files for `Decorators` and `Functions`, incorporating detailed unit tests for decorators and DI functionalities. Removed outdated and redundant test files, consolidating their functionality into the updated tests. Also added new npm script for jest watch mode. Marked helper and main index files to be ignored by the coverage.
