Improve results page UX consistency and interaction flow

## Problem
The results page UX feels slightly inconsistent with the rest of the app and interrupts the analysis flow.

- Users need to scroll back up or navigate backward to analyze another article
- The entire page scrolls, which feels less app-like
- The AI Discussion panel always stays visible, even when focus is on analysis

## Proposed Update
Light UX refinements to improve consistency and flow:

- Make the results page consistent with the overall app theme
- Only the main results area scrolls; header and “Analyze another article” stay fixed
- Allow analyzing another article without scrolling back or navigating away
- Make the AI Discussion panel collapsible into a small bottom-right chat button

I’ve implemented this locally and here's the before/after screenshots:
## Before:

## After:

@ParagGhatage Once approved, I’ll open a PR with the changes.