Fix transcript auto-scroll to stay within panel

[liorboord]

*Issue #200 *

Description of changes:

• Replaced the transcript auto-scroll logic with a helper that scrolls only the transcript container, so the rest of the page stays scrollable during live meetings.
• Updated the “Resume” banner button to use the same helper.
• Added an explicit height for the transcript pane (34 vh / 68 vh) so it doesn’t grow with new transcript entries.

Testing:

1. Joined a live meeting, kept Auto Scroll on, and confirmed the page no longer jumps to the bottom—only the transcript pane scrolls.
2. Scrolled up inside the transcript and verified auto-scroll pauses and resumes correctly.
3. Toggled the sentiment panel collapsed/expanded and confirmed the transcript pane maintains its fixed height.

Fixes #200.