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/components/__init__.py

@@ -0,0 +1,14 @@
+"""Shared Dash components for the portfolio application."""
+
+from .map_controls import create_map_controls, create_metric_selector
+from .metric_card import MetricCard, create_metric_cards_row
+from .time_slider import create_time_slider, create_year_selector
+
+__all__ = [
+    "create_map_controls",
+    "create_metric_selector",
+    "create_time_slider",
+    "create_year_selector",
+    "MetricCard",
+    "create_metric_cards_row",
+]