Redundant os.Stat call per directory entry duplicates information already in DirEntry

[dolph]

Summary

os.ReadDir returns fs.DirEntry values that already carry IsDir() (and on most filesystems, the type is reported by getdents64/readdir without an extra stat). find-replace ignores this and immediately calls os.Stat on every entry via File.Info():

func (fr *findReplace) HandleFile(f *File) {
    if f.Info().IsDir() { ... }       // <- os.Stat
    ...
}

For a tree with N entries this doubles the syscall count. On a tree the size of the OpenStack nova repo (the README's benchmark target, ~6k files), that's ~6k extra syscalls per run.

Impact (Performance: Medium)

• Wall-clock overhead, especially on slow/networked filesystems where stat is a roundtrip.
• Less metadata cache pressure on the OS.
• Stat also follows symlinks (see Symlink traversal can rewrite/rename arbitrary files outside the working directory #2 — security issue), so removing it fixes two birds.

Suggested Fix

• Pass the fs.DirEntry from ReadDir directly into HandleFile, and use entry.Type() / entry.IsDir() / entry.Info() only when needed (and Info() on a DirEntry is itself often free on Unix).
• Remove the lazy os.Stat in File.Info() for the dispatch decision.

Files

• find_replace.go:54-73, 79-94
• file_handling.go:34-43