New msal-browser sample enabling version switching at runtime

[tnorling]

Adds a new sample that includes the ability to switch versions at runtime (both local development builds and any published version). This will be used to test upgrade and downgrade scenarios both manually and in CI.

[Copilot]

Pull Request Overview

Adds a new Express-based sample for msal-browser that demonstrates runtime version switching of the MSAL library.

• Introduces a version switcher UI and backing API endpoints in server.js
• Adds Handlebars views, public JS (including versionSwitcher.js), and CSS for the sample
• Provides a starter README for running and using the sample

Reviewed Changes

Copilot reviewed 22 out of 23 changed files in this pull request and generated 2 comments.

File	Description
samples/msal-browser-samples/ExpressSample/server.js	New API endpoints and logic for dynamic MSAL versioning
samples/msal-browser-samples/ExpressSample/public/js/versionSwitcher.js	UI logic for version dropdown, custom version modal
samples/msal-browser-samples/ExpressSample/public/css/styles.css	Styles for version switcher, modals, and general UI
samples/msal-browser-samples/ExpressSample/README.md	Initial instructions (missing version switcher docs)

Comments suppressed due to low confidence (2)

samples/msal-browser-samples/ExpressSample/server.js:184

• Consider adding unit tests for the /api/version endpoint (and other versioning endpoints) to verify correct JSON responses and cache behavior under different scenarios.

app.get('/api/version', async (req, res) => {

samples/msal-browser-samples/ExpressSample/README.md:70

• The README doesn't yet document the new version switcher feature. Add a section describing how to use the version dropdown and custom version modal.

- The Profile page will automatically fetch and display your user information from MS Graph.

[hectormmg]

This is great!

Non-blocking but if you think it's a good idea maybe we can add an alert in the sample UI for when the environment variables haven't been set. I spent like 30 min re-installing and building before I realized that's why it wasn't working for me.

[tnorling]

This is great!

Non-blocking but if you think it's a good idea maybe we can add an alert in the sample UI for when the environment variables haven't been set. I spent like 30 min re-installing and building before I realized that's why it wasn't working for me.

Let me see what I can do. At the very least I'll make sure an .env file is included here to be more obvious, I guess it got ignored by git