refactor: multi-dashboard structural migration

- Rename dbt project from toronto_housing to portfolio
- Restructure dbt models into domain subdirectories:
  - shared/ for cross-domain dimensions (dim_time)
  - staging/toronto/, intermediate/toronto/, marts/toronto/
- Update SQLAlchemy models for raw_toronto schema
- Add explicit cross-schema FK relationships for FactRentals
- Namespace figure factories under figures/toronto/
- Namespace notebooks under notebooks/toronto/
- Update Makefile with domain-specific targets and env loading
- Update all documentation for multi-dashboard structure

This enables adding new dashboard projects (e.g., /football, /energy)
without structural conflicts or naming collisions.

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

docs/runbooks/adding-dashboard.md

@@ -10,7 +10,9 @@ This runbook describes how to add a new data dashboard to the portfolio applicat
 
 ## Directory Structure
 
-Create the following structure under `portfolio_app/`:
+Create the following structure:
+
+### Application Code (`portfolio_app/`)
 
 ```
 portfolio_app/
@@ -33,8 +35,40 @@ portfolio_app/
 │   │   └── __init__.py
 │   ├── schemas/              # Pydantic models
 │   │   └── __init__.py
-│   └── models/               # SQLAlchemy ORM
+│   └── models/               # SQLAlchemy ORM (schema: raw_{dashboard_name})
 │       └── __init__.py
+└── figures/
+    └── {dashboard_name}/     # Figure factories for this dashboard
+        ├── __init__.py
+        └── ...               # Chart modules
+```
+
+### dbt Models (`dbt/models/`)
+
+```
+dbt/models/
+├── staging/
+│   └── {dashboard_name}/     # Staging models
+│       ├── _sources.yml      # Source definitions (schema: raw_{dashboard_name})
+│       ├── _staging.yml      # Model tests/docs
+│       └── stg_*.sql         # Staging models
+├── intermediate/
+│   └── {dashboard_name}/     # Intermediate models
+│       ├── _intermediate.yml
+│       └── int_*.sql
+└── marts/
+    └── {dashboard_name}/     # Mart tables
+        ├── _marts.yml
+        └── mart_*.sql
+```
+
+### Documentation (`notebooks/`)
+
+```
+notebooks/
+└── {dashboard_name}/         # Domain subdirectories
+    ├── overview/
+    ├── ...
 ```
 
 ## Step-by-Step Checklist
@@ -47,24 +81,47 @@ portfolio_app/
 - [ ] Create loaders in `{dashboard_name}/loaders/`
 - [ ] Add database migrations if needed
 
-### 2. dbt Models
+### 2. Database Schema
+
+- [ ] Define schema constant in models (e.g., `RAW_FOOTBALL_SCHEMA = "raw_football"`)
+- [ ] Add `__table_args__ = {"schema": RAW_FOOTBALL_SCHEMA}` to all models
+- [ ] Update `scripts/db/init_schema.py` to create the new schema
+
+### 3. dbt Models
 
 Create dbt models in `dbt/models/`:
 
-- [ ] `staging/stg_{source}__{entity}.sql` - Raw data cleaning
-- [ ] `intermediate/int_{domain}__{transform}.sql` - Business logic
-- [ ] `marts/mart_{domain}.sql` - Final analytical tables
+- [ ] `staging/{dashboard_name}/_sources.yml` - Source definitions pointing to `raw_{dashboard_name}` schema
+- [ ] `staging/{dashboard_name}/stg_{source}__{entity}.sql` - Raw data cleaning
+- [ ] `intermediate/{dashboard_name}/int_{domain}__{transform}.sql` - Business logic
+- [ ] `marts/{dashboard_name}/mart_{domain}.sql` - Final analytical tables
+
+Update `dbt/dbt_project.yml` with new subdirectory config:
+```yaml
+models:
+  portfolio:
+    staging:
+      {dashboard_name}:
+        +materialized: view
+        +schema: staging
+```
 
 Follow naming conventions:
 - Staging: `stg_{source}__{entity}`
 - Intermediate: `int_{domain}__{transform}`
 - Marts: `mart_{domain}`
 
-### 3. Visualization Layer
+### 4. Visualization Layer
 
-- [ ] Create figure factories in `figures/` (or reuse existing)
+- [ ] Create figure factories in `figures/{dashboard_name}/`
+- [ ] Create `figures/{dashboard_name}/__init__.py` with exports
 - [ ] Follow the factory pattern: `create_{chart_type}_figure(data, **kwargs)`
 
+Import pattern:
+```python
+from portfolio_app.figures.{dashboard_name} import create_choropleth_figure
+```
+
 ### 4. Dashboard Pages
 
 #### Main Dashboard (`pages/{dashboard_name}/dashboard.py`)