Follow-up to #540: a build without the `mcp` feature (`--no-default-features`) still listed
`pdfcraft-cli mcp` in its usage, and `pdfcraft-cli mcp` then said "unknown command".
USAGE is now put together with `concat!`, and its `mcp` lines come from a macro that is empty
without the feature. In such a build `pdfcraft-cli mcp` says the MCP server was left out instead
of calling it an unknown command.
- tests/help.rs: usage_lists_mcp_only_when_built_with_it (runs in both feature sets) and
mcp_without_the_feature_says_it_was_left_out (without the feature)
Co-authored-by: lloyd <lloyd@stackworx.io>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>
The per-command options lived only in main.rs's doc header, so a packaged
binary had no way to show them. They move into a USAGE constant (one copy,
no drift) that `--help`, `-h`, `help` and `<command> --help` print to stdout,
exiting 0. No command prints the usage to stderr and fails; an unknown
command is named and points to --help.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
