feat: Introduce LLM response caching and streaming, add application configuration, and enhance session data with progress and history tracking.

config/llm_config copy.py

@@ -20,7 +20,7 @@ class LLMConfig:
     provider: str = os.environ.get("LLM_PROVIDER", "openai")  # openai, gemini, etc.
     api_key: str = os.environ.get("OPENAI_API_KEY", "sk-2187174de21548b0b8b0c92129700199")
     base_url: str = os.environ.get("OPENAI_BASE_URL", "http://127.0.0.1:9999/v1")
-    model: str = os.environ.get("OPENAI_MODEL", "gemini-3-flash")
+    model: str = os.environ.get("OPENAI_MODEL", "gemini--flash")
     temperature: float = 0.5
     max_tokens: int = 131072