T-001: Scaffold project directory structure

## Phase 1 — Project Setup

**Task**: Scaffold `src/smartcafe/api/`, `domain/`, `adapters/`, `core/` and `tests/unit/`, `tests/functional/` with `__init__.py` in each.

**Effort**: 30 seconds

**Depends on**: —

**Acceptance Criteria**: All directories exist; `python -c "import src.smartcafe"` succeeds.