Smoother interview chat scrolling

• Interview chat no longer auto-scrolls to assistant messages before they have visible text, eliminating jumpy scroll behavior.
• The sticky footer now has an opaque background so message text doesn't bleed through underneath.
• Signed-in users who land on the sign-in or signup page without a redirect target now go to the research dashboard instead of the homepage.

Routine security and dependency updates to keep your data safe.