fix[faustwp-cli]: (#1850) detect HTTP Basic Auth and show accurate error

[latenighthackathon]

Description

When a WordPress site is protected with HTTP Basic Authentication, the secret key validation request returns a 401 from the web server (Apache/Nginx), not from FaustWP. The health check assumed any 401 meant the secret key was wrong, showing a misleading error:

Ensure your FAUST_SECRET_KEY environment variable matches your Secret Key in the Faust WordPress plugin settings

This PR checks the WWW-Authenticate response header for Basic to distinguish between HTTP Basic Auth (web server blocking the request) and a genuine secret key mismatch (FaustWP rejecting the key). Each case now shows an accurate error message.

Related Issues

Closes #1850

Testing

Confirm the issue (before the fix)

1. Verify the health check does not distinguish Basic Auth from secret key mismatch:

grep -A 5 'response.status === 401' packages/faustwp-cli/src/healthCheck/validateFaustEnvVars.ts
# Expected on canary: single error message about FAUST_SECRET_KEY, no WWW-Authenticate check

Confirm the fix

2. Verify the health check now checks WWW-Authenticate header:

grep -A 12 'response.status === 401' packages/faustwp-cli/src/healthCheck/validateFaustEnvVars.ts
# Expected: wwwAuth check for 'basic', two different error paths

3. Verify the new test case passes:

npx jest --config packages/faustwp-cli/jest.config.js --verbose -- validateFaustEnvVars
# Expected: 6 tests pass, including "logs a Basic Auth error when the site returns 401 with WWW-Authenticate: Basic"

4. Verify the existing 401 test still passes (secret key mismatch without Basic Auth):

npx jest --config packages/faustwp-cli/jest.config.js --verbose -- validateFaustEnvVars
# Expected: "logs an error when the secret key validation fails" still passes

Run the test suites

CLI tests:

npx jest --config packages/faustwp-cli/jest.config.js

Full JS tests:

npm install && npm run build && npm run test

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[changeset-bot]

🦋 Changeset detected

Latest commit: a175382

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@faustwp/cli	Patch

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