[SBA-04] initialize passkeys demo app

[jamaljsr]

Summary

This PR introduces the passkeys-demo app as a copy of the existing connect-demo. This establishes a baseline demo application that will be incrementally enhanced with passkey and session-based authentication features in subsequent PRs.

The demo app is intentionally introduced early in the PR stack so that new authentication features can be tested in a realistic React application as they are implemented, rather than waiting until all library code is complete.

Screenshots

Technical Notes

• The passkeys-demo is a direct copy of connect-demo at this stage—no new functionality has been added yet
• Future PRs will update this demo to showcase passkey registration/login and session-based auto-connect flows

Steps to Test

1. Create a link for the lnc-web project

   yarn link
   

2. Navigate to the demo directory:

   cd demos/passkeys-demo
   

3. Install dependencies:

   yarn install
   

4. Link the demo to use the local lnc-web project instead of the NPM package

   yarn link @lightninglabs/lnc-web
   

5. Start the development server:

   yarn start
   

6. Verify the app loads and behaves identically to connect-demo
   • connect with a pairing phrase and confirm the GetInfo response is displayed
   • reload the page and confirm login works

Alternatively, run the library tests from the project root to ensure the build still works:

yarn lint && yarn typecheck && yarn prettier && yarn build && yarn test:coverage

Related Issues & Pull Requests

• Session-Based Authentication & Passkeys #128

Depends on:

• [SBA-03] extract WASM functions from LNC into WasmManager class #132

[lightninglabs-deploy]

@jbrill: review reminder

[jbrill]

LGTM. Don't think it makes sense to critique the sample app code itself. The images and README look good!