✨ feat(vscode): handoff 会话包 stage/pack/unpack/install

Claude-Session: https://claude.ai/code/session_011cEyL6k351U2BzX1Qmygph

vscode/src/cc/handoffArchive.ts

@@ -0,0 +1,25 @@
+import { execFile } from 'node:child_process'
+import { promises as fsp } from 'node:fs'
+import * as path from 'node:path'
+
+function tar(args: string[]): Promise<void> {
+  return new Promise((resolve, reject) => {
+    execFile('tar', args, { timeout: 120_000 }, (err, _stdout, stderr) => {
+      if (err) {
+        reject(new Error(`tar ${args[0]} 失败: ${(stderr ?? '').toString().trim() || err.message}`))
+        return
+      }
+      resolve()
+    })
+  })
+}
+
+export async function packHandoff(stagingDir: string, outFile: string): Promise<void> {
+  await fsp.mkdir(path.dirname(outFile), { recursive: true })
+  await tar(['-czf', outFile, '-C', stagingDir, '.'])
+}
+
+export async function unpackHandoff(archive: string, dstDir: string): Promise<void> {
+  await fsp.mkdir(dstDir, { recursive: true })
+  await tar(['-xzf', archive, '-C', dstDir])
+}