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>

dbt/models/marts/toronto/mart_neighbourhood_overview.sql

@@ -128,7 +128,8 @@ final as (
         -- Component scores (0-100)
         round(safety_score::numeric, 1) as safety_score,
         round(affordability_score::numeric, 1) as affordability_score,
-        -- Amenity score not available at this level, use placeholder
+        -- TODO: Replace with actual amenity score when fact_amenities is populated
+        -- Currently uses neutral placeholder (50.0) which affects livability_score accuracy
         50.0 as amenity_score,
 
         -- Composite livability score: safety (40%), affordability (40%), amenities (20%)