Refact: sandbox quickstart.md & add tutorial for code exec component (#14786)

### What problem does this PR solve?

Refact: sandbox quickstart.md && add tutorial for code exec component

### Type of change

- [x] Refactoring


<img width="700" alt="img_v3_0211j_dcff835b-e3bb-4c77-9bc5-3b31a983229g"
src="https://github.com/user-attachments/assets/7842fc0f-639a-458f-b164-bc81a99ce4a5"
/>

---------

Co-authored-by: writinwaters <93570324+writinwaters@users.noreply.github.com>

web/src/pages/agent/form-sheet/next.tsx

@@ -10,7 +10,7 @@ import { IModalProps } from '@/interfaces/common';
 import { RAGFlowNodeType } from '@/interfaces/database/agent';
 import { cn } from '@/lib/utils';
 import { lowerFirst } from 'lodash';
-import { CirclePlay, X } from 'lucide-react';
+import { ArrowUpRight, CirclePlay, X } from 'lucide-react';
 import { Operator } from '../constant';
 import { AgentFormContext } from '../context';
 import { RunTooltip } from '../flow-tooltip';
@@ -31,6 +31,8 @@ interface IProps {
 }
 
 const EmptyContent = () => <div></div>;
+const SandboxQuickstartUrl =
+  'https://github.com/infiniflow/ragflow/blob/main/docs/guides/agent/agent_quickstarts/sandbox_quickstart.md';
 
 const FormSheet = ({
   visible,
@@ -100,6 +102,24 @@ const FormSheet = ({
                 {t(
                   `${lowerFirst(operatorName === Operator.Tool ? toolComponentName : operatorName)}Description`,
                 )}
+                {operatorName === Operator.Code && (
+                  <Button
+                    variant="ghost"
+                    size="icon"
+                    className="ml-1 inline-flex size-5 !p-0 align-middle bg-transparent"
+                    type="button"
+                    onClick={(e) => {
+                      e.stopPropagation();
+                      window.open(
+                        SandboxQuickstartUrl,
+                        '_blank',
+                        'noopener,noreferrer',
+                      );
+                    }}
+                  >
+                    <ArrowUpRight className="size-4 cursor-pointer text-text-secondary" />
+                  </Button>
+                )}
               </p>
             )}
           </section>