# CRM Step 03 — Backend: Orders CRUD

## Context
Read `.claude/crm-build-plan.md` first for full data models, conventions, and IMPORTANT NOTES.
Steps 01 and 02 must be complete.

## Task
Add Orders models, service, and router to `backend/crm/`.

## What to build

### 1. Add to `backend/crm/models.py`

**Enums:**
- `OrderStatus` — draft, confirmed, in_production, shipped, delivered, cancelled
- `PaymentStatus` — pending, partial, paid

**Structs:**
- `OrderDiscount` — type (str: "percentage" | "fixed"), value (float default 0), reason (Optional[str])
- `OrderShipping` — method (Optional[str]), tracking_number (Optional[str]), carrier (Optional[str]), shipped_at (Optional[str]), delivered_at (Optional[str]), destination (Optional[str])
- `OrderItem`:
  - type: str (console_device | product | freetext)
  - product_id: Optional[str]
  - product_name: Optional[str]
  - description: Optional[str]    ← for freetext items
  - quantity: int default 1
  - unit_price: float default 0.0
  - serial_numbers: List[str] default []

**Order models:**
- `OrderCreate` — customer_id (str), order_number (Optional[str] — auto-generated if not provided), status (OrderStatus default draft), items (List[OrderItem] default []), subtotal (float default 0), discount (Optional[OrderDiscount]), total_price (float default 0), currency (str default "EUR"), shipping (Optional[OrderShipping]), payment_status (PaymentStatus default pending), invoice_path (Optional[str]), notes (Optional[str])
- `OrderUpdate` — all fields Optional
- `OrderInDB` — extends OrderCreate + id, created_at, updated_at
- `OrderListResponse` — orders: List[OrderInDB], total: int

### 2. Add to `backend/crm/service.py`
Firestore collection: `crm_orders`

Auto order number generation: `ORD-{YYYY}-{NNN}` — query existing orders for current year, increment max.

Functions:
- `list_orders(customer_id=None, status=None, payment_status=None) -> List[OrderInDB]`
- `get_order(order_id) -> OrderInDB` — 404 if not found
- `create_order(data: OrderCreate) -> OrderInDB` — auto-generate order_number if not set
- `update_order(order_id, data: OrderUpdate) -> OrderInDB`
- `delete_order(order_id) -> None`

### 3. Add to `backend/crm/router.py`
Prefix `/api/crm/orders`:
- `GET /` — list_orders (query: customer_id, status, payment_status)
- `GET /{order_id}` — get_order
- `POST /` — create_order
- `PUT /{order_id}` — update_order
- `DELETE /{order_id}` — delete_order

Register in `backend/main.py`.

## Notes
- subtotal and total_price are stored as-is (calculated by frontend before POST/PUT). Backend does not recalculate.
- Order number generation doesn't need to be atomic/perfect — just a best-effort sequential label.