Copied session answers now paste as readable text, plus welcome screen fixes

Loading time right after sign-up is now shorter.

• Copy to clipboard in analysis sessions now pastes as readable text and tables for answers that include tables, charts, or reports, with no raw data dumped in front of the text.
• The welcome card that greets participants no longer fades in twice at the start of an embedded conversation. It enters once and stays put.
• Participants in right-to-left languages such as Hebrew and Arabic who return to an unfinished conversation now see the message inviting them to pick up where they left off aligned to the right edge, like the rest of the screen.