[FEAT] Lack of Unified Test Coverage Reporting

Description

There is no unified or automated way to generate and view test coverage reports across all test suites. This makes it difficult to assess overall test coverage and identify untested code paths.

Environment

• Chainlink repo: develop branch
• Go 1.22+
• OS: Linux 6.11.0-29-generic

Examples

• No top-level script or Makefile target for generating a combined coverage report.
• Individual packages may generate coverage, but not aggregated.

Steps to Reproduce

1. Attempt to generate a unified coverage report (e.g., go test -coverprofile=coverage.out ./...).
2. Observe that results are fragmented or missing for some packages.

Additional Info

• Consider adding a Makefile target or script for unified coverage.
• Use tools like go tool cover to visualize combined coverage.

Start by examining the repository's existing test commands and any top-level Makefile or scripts, then run the reported go test -coverprofile=coverage.out ./... command to identify fragmented or missing results. Compare the package outputs with go tool cover and define a unified report workflow. Done means a documented or automated top-level command generates and makes the combined coverage report viewable across the test suites.