docs: update docs and readme

docs/en/knowledge/index.mdx

@@ -5,6 +5,10 @@ description: CowAgent personal knowledge base — structured knowledge accumulat
 
 The personal knowledge base is the Agent's long-term structured knowledge store, saved in the `knowledge/` directory within the workspace. Unlike memory, which is organized by timeline, the knowledge base organizes content by topic — articles, conversation insights, and learning materials are structured into interlinked Markdown pages, forming a continuously growing knowledge network.
 
+<Frame>
+  <img src="https://cdn.link-ai.tech/doc/20260413105435.png" width="800" />
+</Frame>
+
 ## Core Concepts
 
 ### Knowledge vs Memory
@@ -43,7 +47,7 @@ Knowledge writing is an autonomous Agent behavior, triggered in these scenarios:
 Each knowledge page includes cross-reference links to related pages, gradually building a knowledge graph.
 
 <Frame>
-  <img src="https://gist.github.com/user-attachments/assets/3ce92f78-1863-4820-8fa8-660c0f2b7f09" alt="Conversational knowledge ingest" />
+  <img src="https://cdn.link-ai.tech/doc/20260413110104.png" width="800" />
 </Frame>
 
 ## Knowledge Retrieval
@@ -63,11 +67,11 @@ The web console provides a dedicated "Knowledge" module with:
 - **Chat integration** — Knowledge document links referenced in Agent replies are clickable for direct navigation
 
 <Frame>
-  <img src="https://gist.github.com/user-attachments/assets/b7b9d6be-0ac1-4c65-803b-2c6b36bd59a7" alt="Knowledge document browsing" />
+  <img src="https://cdn.link-ai.tech/doc/17aad553d3e9e428c52ff9dc31726fda.png" width="800" />
 </Frame>
 
 <Frame>
-  <img src="https://gist.github.com/user-attachments/assets/44ae68ca-96cc-40b9-ab33-cdbec34c2379" alt="Knowledge graph visualization" />
+  <img src="https://cdn.link-ai.tech/doc/20260413105402.png" width="800" />
 </Frame>
 
 ## CLI Commands