feat: enable media file handling and allow manual assignment of letter public_id

backend/letters/models.py

@@ -16,7 +16,7 @@ class Letter(models.Model):
         SEALED = "SEALED", "Sealed"
         BURNED = "BURNED", "Burned"
 
-    public_id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    public_id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=True)
     user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="letters")
     type = models.CharField(max_length=10, choices=Type.choices, default=Type.KEPT)
     status = models.CharField(max_length=10, choices=Status.choices, default=Status.DRAFT)

backend/letters/serializers.py

@@ -30,7 +30,7 @@ class LetterSerializer(serializers.ModelSerializer):
             "updated_at",
             "images",
         ]  # user to be fetched from request
-        read_only_fields = ["public_id", "created_at", "updated_at"]
+        read_only_fields = ["created_at", "updated_at"]
 
     def validate(self, data):
         if (data.get("encrypted_content") or data.get("encrypted_metadata")) and not data.get("encrypted_dek"):