feat(v2): add multiple extra features from the pdf slides

backend/processing/models.py

@@ -28,6 +28,26 @@ class ImageSession(models.Model):
         return timezone.now() >= self.expires_at
 
 
+class ImageState(models.Model):
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    session = models.ForeignKey(ImageSession, related_name="states", on_delete=models.CASCADE)
+    parent = models.ForeignKey("self", related_name="children", on_delete=models.SET_NULL, null=True, blank=True)
+    sequence = models.PositiveIntegerField(default=0)
+    label = models.CharField(max_length=120)
+    operation = models.CharField(max_length=96)
+    params = models.JSONField(default=dict, blank=True)
+    image = models.CharField(max_length=255)
+    width = models.PositiveIntegerField()
+    height = models.PositiveIntegerField()
+    channels = models.PositiveSmallIntegerField()
+    color_mode = models.CharField(max_length=16)
+    histogram = models.JSONField(default=dict)
+    created_at = models.DateTimeField(auto_now_add=True)
+
+    class Meta:
+        ordering = ["sequence", "created_at"]
+
+
 class ProcessingJob(models.Model):
     STATUS_PENDING = "pending"
     STATUS_RUNNING = "running"