Add user-household associations

[anth-volk]

Summary

Allow users to associate stored households with their accounts, enabling personalized household management and quick access to saved configurations.

Dependencies

• Requires Add stored household CRUD support #74 (Stored household CRUD support)

Scope

Models

• UserHouseholdAssociation model with:
  • user_id (FK to users)
  • household_id (FK to households)
  • label (optional user-specific label)
  • Unique constraint on (user_id, household_id)

Endpoints

• POST /user-household-associations - Create an association
• GET /user-household-associations - List associations (filterable by user_id, household_id)
• GET /user-household-associations/{id} - Get an association by ID
• PUT /user-household-associations/{id} - Update an association (label)
• DELETE /user-household-associations/{id} - Delete an association

Database

• Migration: 20260203000001_create_user_household_associations.sql

Acceptance Criteria

• UserHouseholdAssociation model created
• CRUD endpoints working
• Unique constraint enforced
• Tests passing
• Migration applied successfully