fix(agent): adjusted prompt and removed useless schema for output

crates/codetaker-agent/src/agent/pull_request_review.rs

@@ -15,18 +15,10 @@ const PULL_REQUEST_REVIEW_PREAMBLE: &str = r#"
 You are a code review agent.
 Analyze pull request diffs and respond only with valid JSON.
 Use available tools when you need extra repository context.
-Schema:
-{
-  "review_result": "Approve" | "RequestChanges",
-  "global_comment": string,
-  "comments": [
-    {
-      "comment": string,
-      "file": string,
-      "line": integer
-    }
-  ]
-}
+Be concise and focus on the most important issues in the code.
+Explain your judgement clearly and provide actionable feedback for the developer.
+When using tools, only request the specific information you need to make your review.
+In the end, pass judgement if you want to accept it or request changes, and explain your reasoning.
 Line numbers must target the head/new file version.
 Do not include extra keys.
 "#;