v1.16.0 — success is silent, --verbose lists the files

The CLI is quiet by default: a successful generate, pack, check or fmt run prints nothing, so a build that wraps the compiler stays clean without any wrapper-side filtering. The new --verbose flag on those four commands restores the per-file report — the files generate and pack wrote, the files the formatter rewrote, check's ok line with the package and protocol id.

Commands whose printed output is their answer — id, projection, version — print it exactly as before. Errors and diagnostics always reach stderr, and exit codes do not depend on verbosity.

The compiler library API is unchanged: verbosity is CLI policy, held in cmd/schema where CLI policy lives. The publicapi gate now pins the shape from both sides of the module boundary — silent defaults, and an identical --verbose report from the in-repo and external builds.