Rename the CLI binary from `kez-cli` to `kez` (via a [[bin]] section in
the package's Cargo.toml; package name and `-p kez-cli` invocations stay
the same so the workspace build, tests, and the cross-test harness are
unaffected).
Then update the READMEs to recommend `cargo install --path` once at the
top of Quick Start, after which every example is the much shorter
`kez ...` form. Mention `cargo run -p kez-cli --` as the dev iteration
alternative for anyone who doesn't want to install.
- rust/README.md: 11 `cargo run -p kez-cli --` → `kez` substitutions,
plus a stale "81 tests" → "99 tests" fix.
- README.md (root): Quick start gains a `cargo install` line.
- rust-sig-server/README.md: Quick start uses `kez-sig-server`
(post-install) with `cargo run` as the dev alternative; "Try it"
section rewritten to use the actual `kez sigchain` CLI (which now
exists) instead of the stale "hand-build via kez-core" workaround.
eae98fead0