AND-402: fix pnpm runner entry detection through junctions

[yaojin3616]

Summary

• resolve the runner entry path before comparing it with import.meta.url
• preserve normal direct execution while allowing Windows junction/symlink path spellings
• add regression coverage for aliased entry paths

Verification

• npm test (89 files, 746 tests)
• npm run typecheck
• manual symlink invocation: runner now executes and returns the expected missing-entry error instead of silently exiting 0

Fixes #341
Closes AND-402

[yaojin3616]

已对照最新 main 完成 review：入口路径经 symlink/junction 后不一致、导致 runner 静默退出 0 的问题，已由 #380（b7e15f7）修复并随 v0.8.1 发布。当前实现比较入口两侧的 realpath，并处理路径解析失败；已有真实子进程回归测试验证链接启动、pnpm 实际执行及退出码传递。此次 main 03df4a6 上 pnpm-runner 测试 22/22 通过。因此按已由 #380 实现关闭，不再重复解决冲突合入。对应 #341。