feat: add Sprint 5 visualization components and Toronto dashboard

- Add figure factories: choropleth, time_series, summary_cards
- Add shared components: map_controls, time_slider, metric_card
- Create Toronto dashboard page with KPI cards, choropleth maps, and time series
- Add dashboard callbacks for interactivity
- Placeholder data for demonstration until QGIS boundaries are complete

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

portfolio_app/figures/__init__.py

@@ -0,0 +1,12 @@
+"""Plotly figure factories for data visualization."""
+
+from .choropleth import create_choropleth_figure
+from .summary_cards import create_metric_card_figure
+from .time_series import create_price_time_series, create_volume_time_series
+
+__all__ = [
+    "create_choropleth_figure",
+    "create_price_time_series",
+    "create_volume_time_series",
+    "create_metric_card_figure",
+]