Mesh Plus 0.1.0a7

Fix the library catalog input race: parse bytes from the same checked regular-file descriptor, and cap actual reads at four MiB plus one overflow-detection byte. Growth and pathname replacement can no longer bypass the bound. Canonical process reader/writer behavior and frozen wire schemas remain compatible.

Validation: 96 source and exact installed native/SSH tests; 82 SSH Plus compatibility regressions against the selected authority; deterministic wheel rebuild with complete source payload verification. The paired Tmux rollout records its separate operational gates.