feat: Sprint 6 polish - methodology, demo data, deployment prep

- Add policy event markers to time series charts
- Create methodology page (/toronto/methodology) with data sources
- Add demo data module for testing without full pipeline
- Update README with project documentation
- Add health check endpoint (/health)
- Add database initialization script
- Export new figure factory functions

Closes #21

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

portfolio_app/figures/__init__.py

@@ -1,12 +1,31 @@
 """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
+from .choropleth import (
+    create_choropleth_figure,
+    create_district_map,
+    create_zone_map,
+)
+from .summary_cards import create_metric_card_figure, create_summary_metrics
+from .time_series import (
+    add_policy_markers,
+    create_market_comparison_chart,
+    create_price_time_series,
+    create_time_series_with_events,
+    create_volume_time_series,
+)
 
 __all__ = [
+    # Choropleth
     "create_choropleth_figure",
+    "create_district_map",
+    "create_zone_map",
+    # Time series
     "create_price_time_series",
     "create_volume_time_series",
+    "create_market_comparison_chart",
+    "create_time_series_with_events",
+    "add_policy_markers",
+    # Summary
     "create_metric_card_figure",
+    "create_summary_metrics",
 ]