Follow symlinked dirs in recursive file mode

[AkashKumar7902]

Summary

• Teach recursive filename enumeration to descend into symlinked directories.
• Keep non-recursive traversal from entering nested symlinked directories.
• Add unit coverage for symlinked directory roots and nested symlinked directories.

Fixes #460

Validation

• go test ./pkg/commands/options -run 'TestEnumerateFiles.*Symlinked' -count=1
• go test ./pkg/commands/options -count=1
• go test ./pkg/commands/... -count=1
• go vet ./pkg/commands/...
• git diff --check

[Copilot]

Pull request overview

This PR updates FilenameOptions file enumeration to follow symlinked directories during recursive traversal (to support ko apply --recursive -f ... use cases), while ensuring non-recursive traversal does not descend into nested symlinked directories.

Changes:

• Replaced filepath.Walk-based enumeration with a custom recursive enumerator that can treat symlinked directories as directories.
• Added cycle prevention for directory traversal via a visited set of resolved absolute paths.
• Added unit tests covering recursive symlinked directory traversal and non-recursive behavior with nested symlinked directories.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
pkg/commands/options/filestuff.go	Implements custom traversal to follow symlinked directories (recursive) while skipping nested directories (non-recursive) and avoiding cycles.
pkg/commands/options/filestuff_test.go	Adds unit coverage for symlinked directory roots / nested symlinked directories behavior.

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[Copilot]

When encountering a symlink, an os.Stat failure causes the entry to be silently ignored unless it was explicitly passed as root. This changes previous behavior for symlinked files discovered during directory traversal (e.g., a broken *.yaml symlink would previously be enumerated and then fail later during os.ReadFile), and can result in missing manifests with no error. Consider treating os.Stat errors as “not a directory” (continue through the normal extension filter / emission path) or returning the error so the user gets a clear failure instead of silently skipping the entry.

Suggested change

	if err != nil {
	// Preserve the old behavior for file-like symlinks: if the entry was
	// passed explicitly, stream it and let later file handling report errors.
	if filename == root {
	files <- filename
	}
	return nil
	}
	isDir = targetInfo.IsDir()
	if err == nil {
	isDir = targetInfo.IsDir()
	}