refactor: multi-dashboard structural migration

- Rename dbt project from toronto_housing to portfolio
- Restructure dbt models into domain subdirectories:
  - shared/ for cross-domain dimensions (dim_time)
  - staging/toronto/, intermediate/toronto/, marts/toronto/
- Update SQLAlchemy models for raw_toronto schema
- Add explicit cross-schema FK relationships for FactRentals
- Namespace figure factories under figures/toronto/
- Namespace notebooks under notebooks/toronto/
- Update Makefile with domain-specific targets and env loading
- Update all documentation for multi-dashboard structure

This enables adding new dashboard projects (e.g., /football, /energy)
without structural conflicts or naming collisions.

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

portfolio_app/figures/__init__.py

@@ -1,61 +1,15 @@
-"""Plotly figure factories for data visualization."""
+"""Plotly figure factories for data visualization.
 
-from .bar_charts import (
-    create_horizontal_bar,
-    create_ranking_bar,
-    create_stacked_bar,
-)
-from .choropleth import (
-    create_choropleth_figure,
-    create_zone_map,
-)
-from .demographics import (
-    create_age_pyramid,
-    create_donut_chart,
-    create_income_distribution,
-)
-from .radar import (
-    create_comparison_radar,
-    create_radar_figure,
-)
-from .scatter import (
-    create_bubble_chart,
-    create_scatter_figure,
-)
-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,
-)
+Figure factories are organized by dashboard domain:
+- toronto/  : Toronto Neighbourhood Dashboard figures
+
+Usage:
+    from portfolio_app.figures.toronto import create_choropleth_figure
+    from portfolio_app.figures.toronto import create_ranking_bar
+"""
+
+from . import toronto
 
 __all__ = [
-    # Choropleth
-    "create_choropleth_figure",
-    "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",
-    # Bar charts
-    "create_ranking_bar",
-    "create_stacked_bar",
-    "create_horizontal_bar",
-    # Scatter plots
-    "create_scatter_figure",
-    "create_bubble_chart",
-    # Radar charts
-    "create_radar_figure",
-    "create_comparison_radar",
-    # Demographics
-    "create_age_pyramid",
-    "create_donut_chart",
-    "create_income_distribution",
+    "toronto",
 ]