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/analyze_task_user.md

@@ -0,0 +1,20 @@
+Please analyze the following task:
+
+Task: {{ task }}
+
+Context: {{ context }}
+
+**Analysis Requirements:**
+1. Is it just a small talk? (If yes, no further plan or analysis is needed)
+2. What is the core objective of the task?
+3. What is the complexity level of the task?
+4. What types of specialized skills are required?
+5. Does the task need to be decomposed into subtasks? (If yes, propose the subtask structure)
+6. How to know the task or the subtasks are impossible to lead to the success after a few rounds of interaction?
+7. What are the expected success criteria?
+
+**Available Sub-Agents and Their Specializations:**
+
+{{ tools_desc }}
+
+Provide a detailed analysis of the task based on the above requirements.