refactor(dbt): migrate to domain-scoped schema names

- Create generate_schema_name macro to use custom schema names directly
- Update dbt_project.yml schemas: staging→stg_toronto, intermediate→int_toronto, marts→mart_toronto
- Add dbt/macros/toronto/ directory for future domain-specific macros
- Fix documentation drift in PROJECT_REFERENCE.md (load-data-only→load-toronto-only)
- Update DATABASE_SCHEMA.md with new schema names
- Update CLAUDE.md database schemas table
- Update adding-dashboard.md runbook with domain-scoped pattern

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

docs/PROJECT_REFERENCE.md

@@ -269,7 +269,7 @@ LOG_LEVEL=INFO
 | `db-init` | Initialize database schema |
 | `db-reset` | Drop and recreate database (DESTRUCTIVE) |
 | `load-data` | Load Toronto data from APIs, seed dev data |
-| `load-data-only` | Load Toronto data without dbt or seeding |
+| `load-toronto-only` | Load Toronto data without dbt or seeding |
 | `seed-data` | Seed sample development data |
 | `run` | Start Dash dev server |
 | `test` | Run pytest |