fix(chat): fix shell command execution output markdown block issue (aws#6995)

## Problem
- fix shell command execution output markdown block issue
- When the child process of bash command execution writes to both stdout
and stderr, we need to main the output is processed in the exact order
it was generated by the child process.

## Solution
- Before this change

![image](https://github.com/user-attachments/assets/59190c23-4f0f-452b-a9bd-8efb25fd440d)

- After this change

![image](https://github.com/user-attachments/assets/e8570eb8-477b-4611-8516-d62ce57b7373)



---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: yueny2020

packages/core/src/codewhispererChat/tools/executeBash.ts

@@ -117,6 +117,14 @@ export interface CommandValidation {
     warning?: string
 }
 
+// Interface for timestamped output chunks
+interface TimestampedChunk {
+    timestamp: number
+    isStdout: boolean
+    content: string
+    isFirst: boolean
+}
+
 export class ExecuteBash {
     private readonly command: string
     private readonly workingDirectory?: string
@@ -207,22 +215,68 @@ export class ExecuteBash {
             const stdoutBuffer: string[] = []
             const stderrBuffer: string[] = []
 
-            let firstChunk = true
-            let firstStderrChunk = true
+            // Use a closure boolean value firstChunk and a function to get and set its value
+            let isFirstChunk = true
+            const getAndSetFirstChunk = (newValue: boolean): boolean => {
+                const oldValue = isFirstChunk
+                isFirstChunk = newValue
+                return oldValue
+            }
+
+            // Use a queue to maintain chronological order of chunks
+            // This ensures that the output is processed in the exact order it was generated by the child process.
+            const outputQueue: TimestampedChunk[] = []
+            let processingQueue = false
+
+            // Process the queue in order
+            const processQueue = () => {
+                if (processingQueue || outputQueue.length === 0) {
+                    return
+                }
+
+                processingQueue = true
+
+                try {
+                    // Sort by timestamp to ensure chronological order
+                    outputQueue.sort((a, b) => a.timestamp - b.timestamp)
+
+                    while (outputQueue.length > 0) {
+                        const chunk = outputQueue.shift()!
+                        ExecuteBash.handleTimestampedChunk(chunk, stdoutBuffer, stderrBuffer, updates)
+                    }
+                } finally {
+                    processingQueue = false
+                }
+            }
+
             const childProcessOptions: ChildProcessOptions = {
                 spawnOptions: {
                     cwd: this.workingDirectory,
                     stdio: ['pipe', 'pipe', 'pipe'],
                 },
                 collect: false,
                 waitForStreams: true,
-                onStdout: (chunk: string) => {
-                    ExecuteBash.handleChunk(firstChunk ? '```console\n' + chunk : chunk, stdoutBuffer, updates)
-                    firstChunk = false
+                onStdout: async (chunk: string) => {
+                    const isFirst = getAndSetFirstChunk(false)
+                    const timestamp = Date.now()
+                    outputQueue.push({
+                        timestamp,
+                        isStdout: true,
+                        content: chunk,
+                        isFirst,
+                    })
+                    processQueue()
                 },
-                onStderr: (chunk: string) => {
-                    ExecuteBash.handleChunk(firstStderrChunk ? '```console\n' + chunk : chunk, stderrBuffer, updates)
-                    firstStderrChunk = false
+                onStderr: async (chunk: string) => {
+                    const isFirst = getAndSetFirstChunk(false)
+                    const timestamp = Date.now()
+                    outputQueue.push({
+                        timestamp,
+                        isStdout: false,
+                        content: chunk,
+                        isFirst,
+                    })
+                    processQueue()
                 },
             }
 
@@ -261,6 +315,17 @@ export class ExecuteBash {
         })
     }
 
+    private static handleTimestampedChunk(
+        chunk: TimestampedChunk,
+        stdoutBuffer: string[],
+        stderrBuffer: string[],
+        updates?: Writable
+    ): void {
+        const buffer = chunk.isStdout ? stdoutBuffer : stderrBuffer
+        const content = chunk.isFirst ? '```console\n' + chunk.content : chunk.content
+        ExecuteBash.handleChunk(content, buffer, updates)
+    }
+
     private static handleChunk(chunk: string, buffer: string[], updates?: Writable) {
         try {
             updates?.write(chunk)