chore: Document process.env.DEBUG in node integration tests README (#16558)

A new "Debugging Tests" section was added to
`dev-packages/node-integration-tests/README.md`.

This section documents the `DEBUG` environment variable, which enables
verbose logging for the integration test suite.

When `DEBUG=1` is set (e.g., `DEBUG=1 yarn test`), the test runner
provides detailed output, including:
*   Test scenario startup information (path, flags, DSN).
*   Docker Compose output when tests use `withDockerCompose`.
*   Child process stdout and stderr.
*   HTTP requests made during tests.
*   Process errors and exceptions.
*   Line-by-line output from test scenarios.

This addition improves discoverability and understanding of the
debugging capabilities, aiding in troubleshooting failing tests and
analyzing test execution flow.

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>

Author: AbhiPrasad

dev-packages/node-integration-tests/README.md

@@ -47,3 +47,20 @@ To run tests with Vitest's watch mode:
 To filter tests by their title:
 
 `yarn test -t "set different properties of a scope"`
+
+## Debugging Tests
+
+To enable verbose logging during test execution, set the `DEBUG` environment variable:
+
+`DEBUG=1 yarn test`
+
+When `DEBUG` is enabled, the test runner will output:
+
+- Test scenario startup information (path, flags, DSN)
+- Docker Compose output when using `withDockerCompose`
+- Child process stdout and stderr output
+- HTTP requests made during tests
+- Process errors and exceptions
+- Line-by-line output from test scenarios
+
+This is particularly useful when debugging failing tests or understanding the test execution flow.