HAPI Chat 0.6.1

External links now open in the operating system's default browser instead of replacing the embedded chat with an unreachable blank page.

Navigation within the configured HAPI hub stays embedded. Native session links, dialogs and image/video viewers retain their behavior. Another hub under a different URL prefix is external, including on the same hostname. Normal clicks, middle clicks, new-tab links and window.open are covered.

Fixes #1. Verified with 36 tests, syntax checks, VS Code host checks and a browser integration check through the extension's actual proxy and message bridge. The live test hub was unavailable; the browser check used a local hub fixture.