Feat: deepseek v4 (infiniflow#14346)

### What problem does this PR solve?

Feat: deepseek v4
### Type of change

- [x] New Feature (non-breaking change which adds functionality)

Author: Magicbook1108

conf/llm_factories.json

@@ -1134,16 +1134,16 @@
             "url": "https://api.deepseek.com/v1",
             "llm": [
                 {
-                    "llm_name": "deepseek-chat",
+                    "llm_name": "deepseek-v4-flash",
                     "tags": "LLM,CHAT,",
-                    "max_tokens": 64000,
+                    "max_tokens": 1000000,
                     "model_type": "chat",
                     "is_tools": true
                 },
                 {
-                    "llm_name": "deepseek-reasoner",
+                    "llm_name": "deepseek-v4-pro",
                     "tags": "LLM,CHAT,",
-                    "max_tokens": 64000,
+                    "max_tokens": 1000000,
                     "model_type": "chat",
                     "is_tools": true
                 }