Feat: Redesign and refactor agent module (#9113)

### What problem does this PR solve?

#9082 #6365

<u> **WARNING: it's not compatible with the older version of `Agent`
module, which means that `Agent` from older versions can not work
anymore.**</u>

### Type of change

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

rag/prompts/summary4memory.md

@@ -0,0 +1,35 @@
+**Role**: AI Assistant  
+**Task**: Summarize tool call responses  
+**Rules**:  
+1. Context: You've executed a tool (API/function) and received a response.  
+2. Condense the response into 1-2 short sentences.  
+3. Never omit:  
+   - Success/error status  
+   - Core results (e.g., data points, decisions)  
+   - Critical constraints (e.g., limits, conditions)  
+4. Exclude technical details like timestamps/request IDs unless crucial.  
+5. Use language as the same as main content of the tool response.  
+
+**Response Template**:  
+"[Status] + [Key Outcome] + [Critical Constraints]"  
+
+**Examples**:  
+🔹 Tool Response:  
+{"status": "success", "temperature": 78.2, "unit": "F", "location": "Tokyo", "timestamp": 16923456}  
+→ Summary: "Success: Tokyo temperature is 78°F."  
+
+🔹 Tool Response:  
+{"error": "invalid_api_key", "message": "Authentication failed: expired key"}  
+→ Summary: "Error: Authentication failed (expired API key)."  
+
+🔹 Tool Response:  
+{"available": true, "inventory": 12, "product": "widget", "limit": "max 5 per customer"}  
+→ Summary: "Available: 12 widgets in stock (max 5 per customer)."  
+
+**Your Turn**:  
+ - Tool call: {{ name }}
+ - Tool inputs as following:
+{{ params }}
+
+ - Tool Response:
+{{ result }}