Windows: deferred implode cleanup leaves payloads with paths over 260 characters

[fengmk2]

Summary

On Windows PowerShell 5.1, vp implode --yes can permanently leave a renamed
data.removing-<PID> directory when the installed dependency tree contains
paths longer than 260 characters.

This was discovered while testing #2346, but should be handled as follow-up
work rather than expanding that PR.

Current behavior

vp implode:

1. Renames the data root to data.removing-<PID>.
2. Starts a detached PowerShell process to delete the renamed root.
3. Exits successfully and reports that removal was scheduled.

The deferred script recursively uses Get-Item, Get-ChildItem, and .NET
File/Directory deletion APIs. PowerShell 5.1 cannot directly reopen some
over-260-character paths. The script retries the same operation 100 times and
then exits without notifying the already-finished vp implode process.

The original data path is available for reinstall, but the old dependency tree
remains on disk.

Example

The failure reproduced with this 280-character path:

C:\Users\fengmk2\AppData\Local\Temp\v556\scenario-10-implode\profile\AppData\Local\vite-plus\data.removing-13596\pkg-pr-new-2346\node_modules\.pnpm\@vitest+browser@4.1.10_vite@8.2.1_vitest@4.1.10\node_modules\@vitest\browser\dist\client\__vitest_browser__\orchestrator-KVYrTcFi.js

Direct lookup under Windows PowerShell 5.1 fails:

Get-Item -LiteralPath $LongPath
# Cannot find path ... because it does not exist.

The file can still be discovered while enumerating its parent directory.

When it occurs

This is most likely with:

• A custom VP_DATA_DIR or VP_HOME under a deeply nested workspace.
• Redirected %LOCALAPPDATA%.
• Long corporate profile or OneDrive paths.
• CI environments that create an isolated user profile under the workspace.
• pnpm virtual-store paths containing package, version, and peer-dependency names.

A normal short default Windows profile passed the same full-payload cleanup.

Reproduction requirements

1. Use Windows PowerShell 5.1.
2. Install Vite+ with full dependencies; do not use VP_SKIP_DEPS_INSTALL.
3. Choose a nested data or monolithic root.
4. Confirm at least one installed path exceeds 260 characters.
5. Run vp implode --yes.
6. Wait for the deferred cleanup process.
7. Check for sibling *.removing-* directories.

Expected behavior

All Vite+-owned roots are removed, or an actionable cleanup failure is
reported. No permanent *.removing-* directory remains.

Suggested direction

Use a long-path-aware native Windows cleanup helper instead of PowerShell 5.1
recursive deletion.

The helper should:

• Use extended-length paths or wide Win32 filesystem APIs.
• Delete reparse points without traversing their targets.
• Wait for the original vp.exe process to exit.
• Operate only on the uniquely renamed root.
• Preserve an immediately reinstalled replacement.
• Retry sharing violations for a bounded period.
• Record an actionable failure if cleanup still cannot complete.

Acceptance tests

• Full dependency installation with an asserted path length over 260 characters.
• Split and monolithic implode.
• Temporarily locked files and dangling pnpm junctions.
• Immediate reinstall after implode.
• No remaining *.removing-* roots.
• Replacement installation remains usable.
• Unrelated files in a shared custom bin remain untouched.