PIN a 4 cifre: migrazione 017, login-pin, pin-users, PUT pin, capoturno via PIN (#59)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/backend/models/api/measurement.py

@@ -2,7 +2,7 @@
 from src.backend.models.api.tipi import UtcDateTime, UtcNaiveInput
 from typing import Optional
 
-from pydantic import BaseModel, ConfigDict, Field
+from pydantic import BaseModel, ConfigDict, Field, model_validator
 
 
 class MeasurementCreate(BaseModel):
@@ -71,8 +71,21 @@ class MeasurementListResponse(BaseModel):
 class MeasurementAuthorisation(BaseModel):
     """Credentials of the supervisor allowing an out-of-tolerance value to stand."""
 
-    supervisor_username: str = Field(..., min_length=1)
-    supervisor_password: str = Field(..., min_length=1)
+    # #59: o username+password, oppure supervisor_user_id+supervisor_pin
+    supervisor_username: Optional[str] = Field(None, min_length=1)
+    supervisor_password: Optional[str] = Field(None, min_length=1)
+    supervisor_user_id: Optional[int] = Field(None, gt=0)
+    supervisor_pin: Optional[str] = Field(None, pattern=r"^[0-9]{4}$")
+
+    @model_validator(mode="after")
+    def _one_credential_pair(self):
+        by_password = self.supervisor_username and self.supervisor_password
+        by_pin = self.supervisor_user_id and self.supervisor_pin
+        if not (by_password or by_pin):
+            raise ValueError(
+                "supervisor credentials required: username+password or user_id+pin"
+            )
+        return self
 
 
 class TaskProgressResponse(BaseModel):