сhore(ci): improve e2e nightly report

[universal-itengineer]

Description

Refactor nested E2E reporting in GitHub Actions by replacing inline shell-based report aggregation with reusable Node.js scripts and JSON-based intermediate reports.

The change introduces dedicated report builders for:

• parsing JUnit XML test results into structured per-cluster JSON reports;
• detecting failed pipeline stages and generating fallback reports when test artifacts are missing;
• rendering a consolidated nested-cluster E2E summary message;
• publishing the summary and failed-test thread to Loop via API.

The workflows were updated to install Node.js dependencies, execute the new scripts through actions/github-script, and pass structured outputs and artifacts between reusable and matrix workflows.

Additional tests, linting configuration, JSDoc annotations, and reporting fixes were added for the new logic, including skipped-test handling and a stricter single-file lookup for report discovery.

Why do we need it, and what problem does it solve?

The previous implementation built E2E summaries with large inline bash scripts in workflows. That approach was hard to maintain, hard to test, and fragile when artifacts were missing or when failures happened before the E2E stage.

This change moves the reporting flow into tested JavaScript modules and uses structured JSON reports as the contract between workflow stages. That makes report generation easier to validate, easier to evolve, and less dependent on brittle shell parsing.

It also improves failure handling by preserving stage-level metadata, distinguishing between test failures and cluster setup failures, supporting missing-artifact scenarios explicitly, and correctly accounting for skipped tests.

As a result, nested-cluster E2E reporting becomes more reliable and maintainable for both successful and failed runs.

What is the expected result?

1. Run the nested E2E workflows for configured storage types.
2. The reusable pipeline produces a structured e2e_report_<storage>.json report based on JUnit XML data or fallback stage metadata.
3. The matrix workflow downloads the generated report artifacts and renders a consolidated summary.
4. The summary message contains:
   • a test results table for clusters with test reports;
   • a separate cluster-failures section for setup-stage or artifact-related failures;
   • a failed-tests thread when testcase-level failures are available.
5. If Loop credentials are configured, both the main message and the thread reply are sent through the Loop API.

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries

section: ci
type: fix
summary: "Refactor nested E2E report generation into tested Node.js scripts with JSON reports and improve Loop reporting for missing artifacts, skipped tests, and stage failures."
impact_level: low

[danilrwx]

why Set?

[universal-itengineer]

const reportKind = preE2EStages.has(stageName) ? "stage-failure" : "tests";

[danilrwx]

maybe move to utils?

[danilrwx]

handle errors

[universal-itengineer]

fixed