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/time_series.py

@@ -231,3 +231,119 @@ def create_market_comparison_chart(
     )
 
     return fig
+
+
+def add_policy_markers(
+    fig: go.Figure,
+    policy_events: list[dict[str, Any]],
+    date_column: str = "event_date",
+    y_position: float | None = None,
+) -> go.Figure:
+    """Add policy event markers to an existing time series figure.
+
+    Args:
+        fig: Existing Plotly figure to add markers to.
+        policy_events: List of policy event dicts with date and metadata.
+        date_column: Column name for event dates.
+        y_position: Y position for markers. If None, uses top of chart.
+
+    Returns:
+        Updated Plotly Figure object with policy markers.
+    """
+    if not policy_events:
+        return fig
+
+    # Color mapping for policy categories
+    category_colors = {
+        "monetary": "#1f77b4",  # Blue
+        "tax": "#2ca02c",  # Green
+        "regulatory": "#ff7f0e",  # Orange
+        "supply": "#9467bd",  # Purple
+        "economic": "#d62728",  # Red
+    }
+
+    # Symbol mapping for expected direction
+    direction_symbols = {
+        "bullish": "triangle-up",
+        "bearish": "triangle-down",
+        "neutral": "circle",
+    }
+
+    for event in policy_events:
+        event_date = event.get(date_column)
+        category = event.get("category", "economic")
+        direction = event.get("expected_direction", "neutral")
+        title = event.get("title", "Policy Event")
+        level = event.get("level", "federal")
+
+        color = category_colors.get(category, "#666666")
+        symbol = direction_symbols.get(direction, "circle")
+
+        # Add vertical line for the event
+        fig.add_vline(
+            x=event_date,
+            line_dash="dot",
+            line_color=color,
+            opacity=0.5,
+            annotation_text="",
+        )
+
+        # Add marker with hover info
+        fig.add_trace(
+            go.Scatter(
+                x=[event_date],
+                y=[y_position] if y_position else [None],  # type: ignore[list-item]
+                mode="markers",
+                marker={
+                    "symbol": symbol,
+                    "size": 12,
+                    "color": color,
+                    "line": {"width": 1, "color": "white"},
+                },
+                name=title,
+                hovertemplate=(
+                    f"<b>{title}</b><br>"
+                    f"Date: %{{x}}<br>"
+                    f"Level: {level.title()}<br>"
+                    f"Category: {category.title()}<br>"
+                    f"<extra></extra>"
+                ),
+                showlegend=False,
+            )
+        )
+
+    return fig
+
+
+def create_time_series_with_events(
+    data: list[dict[str, Any]],
+    policy_events: list[dict[str, Any]],
+    date_column: str = "full_date",
+    value_column: str = "avg_price",
+    title: str = "Price Trend with Policy Events",
+) -> go.Figure:
+    """Create a time series chart with policy event markers.
+
+    Args:
+        data: Time series data.
+        policy_events: Policy events to overlay.
+        date_column: Column name for dates.
+        value_column: Column name for values.
+        title: Chart title.
+
+    Returns:
+        Plotly Figure with time series and policy markers.
+    """
+    # Create base time series
+    fig = create_price_time_series(
+        data=data,
+        date_column=date_column,
+        price_column=value_column,
+        title=title,
+    )
+
+    # Add policy markers at the top of the chart
+    if policy_events:
+        fig = add_policy_markers(fig, policy_events)
+
+    return fig