Support DeepSeek V4 Flash Vision Experimental

migrations/20261004000000_allow_deepseek_vision_session_model/down.sql

@@ -0,0 +1,14 @@
+ALTER TABLE sessions ADD COLUMN model_without_deepseek_vision TEXT
+    CHECK (model_without_deepseek_vision IS NULL OR model_without_deepseek_vision IN (
+        'deepseek-v4-flash-0731',
+        'deepseek-v4-pro',
+        'glm-5.2',
+        'glm-5.3-flash',
+        'qwen3.8-flash-next'
+    ));
+UPDATE sessions SET model_without_deepseek_vision = CASE
+    WHEN model = 'deepseek-v4-flash-vision-exp' THEN NULL
+    ELSE model
+END;
+ALTER TABLE sessions DROP COLUMN model;
+ALTER TABLE sessions RENAME COLUMN model_without_deepseek_vision TO model;