Add flag field to Submission model with FlagChoices enum

Adds red/blue/green/yellow flag options for marking submissions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

submission/migrations/0004_submission_flag.py

@@ -0,0 +1,18 @@
+# Generated by Django 6.0.1 on 2026-03-09 09:22
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('submission', '0003_submission_conversation'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='submission',
+            name='flag',
+            field=models.CharField(blank=True, choices=[('red', '值得展示'), ('blue', '需要讲解'), ('green', '优秀作品'), ('yellow', '需要改进')], default=None, max_length=10, null=True, verbose_name='标记'),
+        ),
+    ]

submission/models.py

@@ -11,6 +11,13 @@ from task.models import Task
 from prompt.models import Conversation
 
 
+class FlagChoices(models.TextChoices):
+    RED = "red", "值得展示"
+    BLUE = "blue", "需要讲解"
+    GREEN = "green", "优秀作品"
+    YELLOW = "yellow", "需要改进"
+
+
 class Submission(TimeStampedModel):
     id = models.UUIDField(
         primary_key=True,
@@ -31,6 +38,14 @@ class Submission(TimeStampedModel):
         Conversation, on_delete=models.SET_NULL, null=True, blank=True,
         related_name="submissions", verbose_name="对话"
     )
+    flag = models.CharField(
+        max_length=10,
+        choices=FlagChoices.choices,
+        null=True,
+        blank=True,
+        default=None,
+        verbose_name="标记",
+    )
 
     class Meta:
         ordering = ("-created",)