Standardize command help and version discovery

[konojunya]

Summary

• add help and version commands with the documented -h, --help, -v, -V, and --version aliases
• expose stable help at every existing command level with examples and process-level snapshots
• return actionable suggestions for close command typos while preserving the established stdout, stderr, and exit-status contract
• exercise the expanded command metadata surface in CI

Validation

• cargo fmt --check
• cargo test --locked
• cargo clippy --all-targets --all-features --locked -- -D warnings
• cargo +1.85.0 test --locked
• cargo +1.85.0 clippy --all-targets --all-features --locked -- -D warnings
• STACK_SPECIFICATION_DIR=/path/to/specification cargo test --features conformance --test formatter-conformance --locked
• cargo llvm-cov --all-features --locked --fail-under-lines 90 --fail-under-functions 95 --fail-under-regions 90
• RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --locked
• cargo build --release --locked
• python3 scripts/validate-render.py