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/toronto/choropleth.py

@@ -0,0 +1,143 @@
+"""Choropleth map figure factory for Toronto housing data."""
+
+from typing import Any
+
+import plotly.express as px
+import plotly.graph_objects as go
+
+
+def create_choropleth_figure(
+    geojson: dict[str, Any] | None,
+    data: list[dict[str, Any]],
+    location_key: str,
+    color_column: str,
+    hover_data: list[str] | None = None,
+    color_scale: str = "Blues",
+    title: str | None = None,
+    map_style: str = "carto-positron",
+    center: dict[str, float] | None = None,
+    zoom: float = 9.5,
+) -> go.Figure:
+    """Create a choropleth map figure.
+
+    Args:
+        geojson: GeoJSON FeatureCollection for boundaries.
+        data: List of data records with location keys and values.
+        location_key: Column name for location identifier.
+        color_column: Column name for color values.
+        hover_data: Additional columns to show on hover.
+        color_scale: Plotly color scale name.
+        title: Optional chart title.
+        map_style: Mapbox style (carto-positron, open-street-map, etc.).
+        center: Map center coordinates {"lat": float, "lon": float}.
+        zoom: Initial zoom level.
+
+    Returns:
+        Plotly Figure object.
+    """
+    # Default center to Toronto
+    if center is None:
+        center = {"lat": 43.7, "lon": -79.4}
+
+    # Use dark-mode friendly map style by default
+    if map_style == "carto-positron":
+        map_style = "carto-darkmatter"
+
+    # If no geojson provided, create a placeholder map
+    if geojson is None or not data:
+        fig = go.Figure(go.Scattermapbox())
+        fig.update_layout(
+            mapbox={
+                "style": map_style,
+                "center": center,
+                "zoom": zoom,
+            },
+            margin={"l": 0, "r": 0, "t": 40, "b": 0},
+            title=title or "Toronto Housing Map",
+            height=500,
+            paper_bgcolor="rgba(0,0,0,0)",
+            plot_bgcolor="rgba(0,0,0,0)",
+            font_color="#c9c9c9",
+        )
+        fig.add_annotation(
+            text="No geometry data available. Complete QGIS digitization to enable map.",
+            xref="paper",
+            yref="paper",
+            x=0.5,
+            y=0.5,
+            showarrow=False,
+            font={"size": 14, "color": "#888888"},
+        )
+        return fig
+
+    # Create choropleth with data
+    import pandas as pd
+
+    df = pd.DataFrame(data)
+
+    # Use dark-mode friendly map style
+    effective_map_style = (
+        "carto-darkmatter" if map_style == "carto-positron" else map_style
+    )
+
+    fig = px.choropleth_mapbox(
+        df,
+        geojson=geojson,
+        locations=location_key,
+        featureidkey=f"properties.{location_key}",
+        color=color_column,
+        color_continuous_scale=color_scale,
+        hover_data=hover_data,
+        mapbox_style=effective_map_style,
+        center=center,
+        zoom=zoom,
+        opacity=0.7,
+    )
+
+    fig.update_layout(
+        margin={"l": 0, "r": 0, "t": 40, "b": 0},
+        title=title,
+        height=500,
+        paper_bgcolor="rgba(0,0,0,0)",
+        plot_bgcolor="rgba(0,0,0,0)",
+        font_color="#c9c9c9",
+        coloraxis_colorbar={
+            "title": {
+                "text": color_column.replace("_", " ").title(),
+                "font": {"color": "#c9c9c9"},
+            },
+            "thickness": 15,
+            "len": 0.7,
+            "tickfont": {"color": "#c9c9c9"},
+        },
+    )
+
+    return fig
+
+
+def create_zone_map(
+    zones_geojson: dict[str, Any] | None,
+    rental_data: list[dict[str, Any]],
+    metric: str = "avg_rent",
+) -> go.Figure:
+    """Create choropleth map for CMHC zones.
+
+    Args:
+        zones_geojson: GeoJSON for CMHC zone boundaries.
+        rental_data: Rental statistics by zone.
+        metric: Metric to display (avg_rent, vacancy_rate, etc.).
+
+    Returns:
+        Plotly Figure object.
+    """
+    hover_columns = ["zone_name", "avg_rent", "vacancy_rate", "rental_universe"]
+
+    return create_choropleth_figure(
+        geojson=zones_geojson,
+        data=rental_data,
+        location_key="zone_code",
+        color_column=metric,
+        hover_data=[c for c in hover_columns if c != metric],
+        color_scale="Oranges" if "rent" in metric else "Purples",
+        title="Toronto Rental Market by Zone",
+    )