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/rank_memory.md

@@ -0,0 +1,30 @@
+**Task**: Sort the tool call results based on relevance to the overall goal and current sub-goal. Return ONLY a sorted list of indices (0-indexed).
+
+**Rules**:
+1. Analyze each result's contribution to both:
+   - The overall goal (primary priority)
+   - The current sub-goal (secondary priority)
+2. Sort from MOST relevant (highest impact) to LEAST relevant
+3. Output format: Strictly a Python-style list of integers. Example: [2, 0, 1]
+
+🔹 Overall Goal: {{ goal }}
+🔹 Sub-goal: {{ sub_goal }}
+
+**Examples**:  
+🔹 Tool Response:  
+ - index: 0
+     > Tokyo temperature is 78°F.
+ - index: 1
+     > Error: Authentication failed (expired API key).
+ - index: 2
+     > Available: 12 widgets in stock (max 5 per customer).
+ 
+ → rank: [1,2,0]<|stop|>
+ 
+
+**Your Turn**:  
+🔹 Tool Response:
+{% for f in results %}
+ - index: f.i
+     > f.content
+{% endfor %}