0.4.3

Fixes a Linux upgrade failure when the private socket is enabled. TCP and Unix listeners no longer leak into runtime subprocesses, so a child cannot keep the old port occupied during automatic re-exec.

Existing sessions started under 0.4.0–0.4.2 may already hold leaked descriptors. Installing this release cannot close those descriptors retroactively. Defer the first upgrade while affected sessions are active; finish work before a coordinated service replacement. A service-manager restart can end tmux sessions and is not a session-preserving workaround.

Validated with a failing-before/passing-after subprocess regression and an isolated Linux tmux probe. No model calls were needed. Local validation passed all 4,868 tests. Packaged Linux re-exec preserved the daemon, tmux server and inert-shell processes. Review and validation are recorded in PR #537.