fix: return fetched content to LLM in web_fetch tool

WebFetchTool.Execute was setting ForLLM to a summary string
("Fetched N bytes from URL ...") instead of the actual extracted
text. This meant the LLM never saw the page content and could not
answer questions based on fetched web pages.

Return the extracted text in ForLLM so the model can use it.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pkg/tools/web.go

@@ -652,13 +652,7 @@ func (t *WebFetchTool) Execute(ctx context.Context, args map[string]any) *ToolRe
 	resultJSON, _ := json.MarshalIndent(result, "", "  ")
 
 	return &ToolResult{
-		ForLLM: fmt.Sprintf(
+		ForLLM:  text,
-			"Fetched %d bytes from %s (extractor: %s, truncated: %v)",
-			len(text),
-			urlStr,
-			extractor,
-			truncated,
-		),
 		ForUser: string(resultJSON),
 	}
 }