refactor: update app code for domain-scoped schema migration

- Update dbt model references to use new schema naming (stg_toronto, int_toronto, mart_toronto)
- Refactor figure factories to use consistent column naming from new schema
- Update callbacks to work with refactored data structures
- Add centralized design tokens module for consistent styling
- Streamline CLAUDE.md documentation

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

portfolio_app/design/__init__.py

@@ -0,0 +1,48 @@
+"""Design system tokens and utilities."""
+
+from .tokens import (
+    CHART_PALETTE,
+    COLOR_ACCENT,
+    COLOR_NEGATIVE,
+    COLOR_POSITIVE,
+    COLOR_WARNING,
+    GRID_COLOR,
+    GRID_COLOR_DARK,
+    PALETTE_COMPARISON,
+    PALETTE_GENDER,
+    PALETTE_TREND,
+    PAPER_BG,
+    PLOT_BG,
+    POLICY_COLORS,
+    TEXT_MUTED,
+    TEXT_PRIMARY,
+    TEXT_SECONDARY,
+    get_colorbar_defaults,
+    get_default_layout,
+)
+
+__all__ = [
+    # Text colors
+    "TEXT_PRIMARY",
+    "TEXT_SECONDARY",
+    "TEXT_MUTED",
+    # Chart backgrounds
+    "GRID_COLOR",
+    "GRID_COLOR_DARK",
+    "PAPER_BG",
+    "PLOT_BG",
+    # Semantic colors
+    "COLOR_POSITIVE",
+    "COLOR_NEGATIVE",
+    "COLOR_WARNING",
+    "COLOR_ACCENT",
+    # Palettes
+    "CHART_PALETTE",
+    "PALETTE_COMPARISON",
+    "PALETTE_GENDER",
+    "PALETTE_TREND",
+    "POLICY_COLORS",
+    # Utility functions
+    "get_default_layout",
+    "get_colorbar_defaults",
+]