@W-20726574 Bring up to date with #3644

[noahadams]

Description

Fixes some edge case bugs in the previous base path handling middleware, adds some more specific testing. Backport of feedback improvements from #3644, followup to #3641

Types of Changes

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Documentation update
• Breaking change (could cause existing functionality to not work as expected)
• Other changes (non-breaking changes that does not fit any of the above)

Breaking changes include:

• Removing a public function or component or prop
• Adding a required argument to a function
• Changing the data type of a function parameter or return value
• Adding a new peer dependency to package.json

Changes

• in template-mrt-reference-app, fixes up base path middleware to detect base path from req.path, and then slice it off of req.url, also handle case where basepath is the only path segment (e.g, not followed by a trailing slash)
• lowers logging to debug level
• adds a deeper test case that checks resolved path and looks for hte base path driving env var in the echo endpoints response

How to Test-Drive This PR

• checkout branch, and with Node.js v22.x installed and active, from checkout root run
• npm ci
• cd packages/template-mrt-reference-app
• npm run test

Checklists

General

• Changes are covered by test cases
• CHANGELOG.md updated with a short description of changes (not required for documentation updates)

Accessibility Compliance

You must check off all items in one of the follow two lists:

• There are no changes to UI

or...

• Changes were tested with a Screen Reader (iOS VoiceOver or Android Talkback) and had no issues
• Changes comply with WCAG 2.0 guidelines levels A and AA
• Changes to common UI patterns and interactions comply with WAI-ARIA best practices

Localization

• Changes include a UI text update in the Retail React App (which requires translation)

[cc-prodsec]

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