fix(core): ai tool calling explanation (#13097)

Close [AI-293](https://linear.app/affine-design/issue/AI-293)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Tool call cards for website reading now display the specific URL being
accessed.
* Tool call cards for web searches now display the search query being
used.

* **Style**
* Updated tool call instructions to prevent explanations of operations
before execution.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/plugins/copilot/prompt/prompts.ts

@@ -1675,6 +1675,7 @@ This sentence contains information from the first source[^1]. This sentence refe
 
 <tool-calling-guidelines>
 Before starting Tool calling, you need to follow:
+- DO NOT explain what operation you will perform.
 - DO NOT embed a tool call mid-sentence.
 - When searching for unknown information or keyword, prioritize searching the user's workspace.
 - Depending on the complexity of the question and the information returned by the search tools, you can call different tools multiple times to search.