feat: Complete Phase 5 dashboard implementation

Implement full 5-tab Toronto Neighbourhood Dashboard with real data
connectivity:

Dashboard Structure:
- Overview tab with livability scores and rankings
- Housing tab with affordability metrics
- Safety tab with crime statistics
- Demographics tab with population/income data
- Amenities tab with parks, schools, transit

Figure Factories (portfolio_app/figures/):
- bar_charts.py: ranking, stacked, horizontal bars
- scatter.py: scatter plots, bubble charts
- radar.py: spider/radar charts
- demographics.py: donut, age pyramid, income distribution

Service Layer (portfolio_app/toronto/services/):
- neighbourhood_service.py: queries dbt marts for all tab data
- geometry_service.py: generates GeoJSON from PostGIS
- Graceful error handling when database unavailable

Callbacks (portfolio_app/pages/toronto/callbacks/):
- map_callbacks.py: choropleth updates, map click handling
- chart_callbacks.py: supporting chart updates
- selection_callbacks.py: dropdown handlers, KPI updates

Data Pipeline (scripts/data/):
- load_toronto_data.py: orchestration script with CLI flags

Lessons Learned:
- Graceful error handling in service layers
- Modular callback structure for multi-tab dashboards
- Figure factory pattern for reusable charts

Closes: #64, #65, #66, #67, #68, #69, #70

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

portfolio_app/figures/scatter.py

@@ -0,0 +1,184 @@
+"""Scatter plot figure factory for correlation views."""
+
+from typing import Any
+
+import pandas as pd
+import plotly.express as px
+import plotly.graph_objects as go
+
+
+def create_scatter_figure(
+    data: list[dict[str, Any]],
+    x_column: str,
+    y_column: str,
+    name_column: str | None = None,
+    size_column: str | None = None,
+    color_column: str | None = None,
+    title: str | None = None,
+    x_title: str | None = None,
+    y_title: str | None = None,
+    trendline: bool = False,
+    color_scale: str = "Blues",
+) -> go.Figure:
+    """Create scatter plot for correlation visualization.
+
+    Args:
+        data: List of data records.
+        x_column: Column name for x-axis values.
+        y_column: Column name for y-axis values.
+        name_column: Column name for point labels (hover).
+        size_column: Column name for point sizes.
+        color_column: Column name for color encoding.
+        title: Optional chart title.
+        x_title: X-axis title.
+        y_title: Y-axis title.
+        trendline: Whether to add OLS trendline.
+        color_scale: Plotly color scale for continuous colors.
+
+    Returns:
+        Plotly Figure object.
+    """
+    if not data:
+        return _create_empty_figure(title or "Scatter Plot")
+
+    df = pd.DataFrame(data)
+
+    # Build hover_data
+    hover_data = {}
+    if name_column and name_column in df.columns:
+        hover_data[name_column] = True
+
+    # Create scatter plot
+    fig = px.scatter(
+        df,
+        x=x_column,
+        y=y_column,
+        size=size_column if size_column and size_column in df.columns else None,
+        color=color_column if color_column and color_column in df.columns else None,
+        color_continuous_scale=color_scale,
+        hover_name=name_column,
+        trendline="ols" if trendline else None,
+        opacity=0.7,
+    )
+
+    # Style the markers
+    fig.update_traces(
+        marker={
+            "line": {"width": 1, "color": "rgba(255,255,255,0.3)"},
+        },
+    )
+
+    # Trendline styling
+    if trendline:
+        fig.update_traces(
+            selector={"mode": "lines"},
+            line={"color": "#FF9800", "dash": "dash", "width": 2},
+        )
+
+    fig.update_layout(
+        title=title,
+        paper_bgcolor="rgba(0,0,0,0)",
+        plot_bgcolor="rgba(0,0,0,0)",
+        font_color="#c9c9c9",
+        xaxis={
+            "gridcolor": "rgba(128,128,128,0.2)",
+            "title": x_title or x_column.replace("_", " ").title(),
+            "zeroline": False,
+        },
+        yaxis={
+            "gridcolor": "rgba(128,128,128,0.2)",
+            "title": y_title or y_column.replace("_", " ").title(),
+            "zeroline": False,
+        },
+        margin={"l": 10, "r": 10, "t": 40, "b": 10},
+        showlegend=color_column is not None,
+    )
+
+    return fig
+
+
+def create_bubble_chart(
+    data: list[dict[str, Any]],
+    x_column: str,
+    y_column: str,
+    size_column: str,
+    name_column: str | None = None,
+    color_column: str | None = None,
+    title: str | None = None,
+    x_title: str | None = None,
+    y_title: str | None = None,
+    size_max: int = 50,
+) -> go.Figure:
+    """Create bubble chart with sized markers.
+
+    Args:
+        data: List of data records.
+        x_column: Column name for x-axis values.
+        y_column: Column name for y-axis values.
+        size_column: Column name for bubble sizes.
+        name_column: Column name for labels.
+        color_column: Column name for colors.
+        title: Optional chart title.
+        x_title: X-axis title.
+        y_title: Y-axis title.
+        size_max: Maximum marker size in pixels.
+
+    Returns:
+        Plotly Figure object.
+    """
+    if not data:
+        return _create_empty_figure(title or "Bubble Chart")
+
+    df = pd.DataFrame(data)
+
+    fig = px.scatter(
+        df,
+        x=x_column,
+        y=y_column,
+        size=size_column,
+        color=color_column,
+        hover_name=name_column,
+        size_max=size_max,
+        opacity=0.7,
+    )
+
+    fig.update_layout(
+        title=title,
+        paper_bgcolor="rgba(0,0,0,0)",
+        plot_bgcolor="rgba(0,0,0,0)",
+        font_color="#c9c9c9",
+        xaxis={
+            "gridcolor": "rgba(128,128,128,0.2)",
+            "title": x_title or x_column.replace("_", " ").title(),
+        },
+        yaxis={
+            "gridcolor": "rgba(128,128,128,0.2)",
+            "title": y_title or y_column.replace("_", " ").title(),
+        },
+        margin={"l": 10, "r": 10, "t": 40, "b": 10},
+    )
+
+    return fig
+
+
+def _create_empty_figure(title: str) -> go.Figure:
+    """Create an empty figure with a message."""
+    fig = go.Figure()
+    fig.add_annotation(
+        text="No data available",
+        xref="paper",
+        yref="paper",
+        x=0.5,
+        y=0.5,
+        showarrow=False,
+        font={"size": 14, "color": "#888888"},
+    )
+    fig.update_layout(
+        title=title,
+        paper_bgcolor="rgba(0,0,0,0)",
+        plot_bgcolor="rgba(0,0,0,0)",
+        font_color="#c9c9c9",
+        xaxis={"visible": False},
+        yaxis={"visible": False},
+    )
+    return fig