Change sentiment heatmap from stacked bar to multi-line chart

Move export button to sidebar above Danger Zone in both files

Replace broken PDF with html2canvas screenshot export on Stats page

Remove confidence trend chart and word cloud from Stats view

Move engagement score section: after cumulative topic, before window snapshot

Move pinned messages from Stats to Comments view - show above feed

Fix duplicate widget key - pages now import from shared.py not app.py

Refactor to multi-page navigation - fix view bleeding permanently