Saving output piped into tail is stricter and safer

When a shell command pipes its output into tail, Claude Code can save that output to a file. tail shows only the last lines. This feature now also writes a marks file and shares its files with the shell more directly. It is applied in fewer cases:

• The command is fully parsed and the tail line count must match.
• It is skipped for eval of quoted strings.
• It is skipped when built-in shell commands are overridden.
• It is skipped when || comes before tail.
• It can refuse when the disk has few free file entries at the start.

Claude Code also checks that the marks are valid. Before, the decision used a simple text match, with no disk check and no marks file.