There was no way to reach a non-default profile: tabs always opened under the
configured default, and nothing in the chrome said which profile you were in.

The "+" surface menu gains a "Browser in profile" submenu. The choice lives at
open time because a tab's profile is fixed then — Electron only honours a
partition before the guest attaches — so offering it on an already-open tab
would promise a switch that cannot happen. The three-dot menu now names the
tab's profile, which was otherwise invisible.

Also routes the two paths that bypassed `openPreviewSession` — opening a file
or an external link in the preview, and the terminal's "open in preview" —
through the configured defaults. Both built their open input by hand, so they
silently ignored the default viewport as well as the profile.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>