M11: implement operational booking lifecycle

backend/app/schemas.py

@@ -69,6 +69,25 @@ class CreateBookingRequest(BaseModel):
     requirements_complete: bool = True
 
 
+class CustomerOptionOut(BaseModel):
+    public_ref: str
+    display_name: str
+    email: str | None
+
+
+class AvailableVehicleOut(BaseModel):
+    public_ref: str
+    make: str
+    model: str
+    registration_number: str
+    location: str
+    operational_status: str
+
+
+class CancelBookingRequest(BaseModel):
+    reason: str = Field(min_length=3, max_length=500)
+
+
 class BookingPageOut(BaseModel):
     items: list[BookingOut]
     page: int