fix: MSW mock endpoint mismatch when dev server runs on non-3000 ports

[Vinyl-Davyl]

Description of the Change

The mock API setup in src/mocks/browser.js previously hardcoded the base URL to:

http://localhost:3000

This caused issues when the React development server started on a different port (e.g. 3001 or 3002) because Mock Service Worker (MSW) intercepts did not match the request origin.

As a result, the mock endpoints failed to intercept API requests during local development.

This change replaces the hardcoded origin with:

window.location.origin

This allows the mock endpoints to dynamically match the current origin of the running application, ensuring that MSW intercepts work regardless of the port used by the development server.

Alternate Designs

Other alternatives considered:

Using a configurable environment variable for the mock base URL.

Detecting the dev server port and dynamically constructing the URL.

However, using window.location.origin was chosen because it is simpler, requires no configuration, and ensures the mock endpoints always match the current application origin.

Possible Drawbacks

None expected. The change only affects local mock endpoint construction and should not impact production behavior.

Verification Process

Steps used to verify the fix:

Started the development server while port 3000 was already in use.

Dev server started on http://localhost:3002.

Observed that mock API requests failed due to the hardcoded localhost:3000 endpoint.

Updated the mock endpoint to use window.location.origin.

Restarted the dev server.

Verified that all mock requests were correctly intercepted by MSW.

Result

Mock API responses were correctly returned regardless of the dev server port. Fixes #177

[Vinyl-Davyl]

cc: @saikonen @romain-intel