chore(scripts): update gemini-flash model name

Author: lzwjava

scripts/llm/openrouter_client.py

@@ -11,7 +11,7 @@
 MODEL_MAPPING = {
     "claude-opus": "anthropic/claude-opus-4.1",
     "claude-sonnet": "anthropic/claude-4.5-sonnet",
-    "gemini-flash": "google/gemini-2.5-flash",
+    "gemini-flash": "google/gemini-3-flash-preview",
     "gemini-pro": "google/gemini-3-pro-preview",
     "kimi-k2": "moonshotai/kimi-k2",
     "deepseek-v3.2": "deepseek/deepseek-v3.2",