Drop the bare `dsh <config>` positional in favor of a `--config <path>` flag.
Without a root positional, `web` can be a real Commander subcommand in one
program instead of the reserved-first-token dispatch to a second parser, so
`dsh --help` lists every mode natively (no hand-pasted command text) and the
second parser + reserved-token machinery are gone.
Grammar:
dsh TUI (shipped tree + ~/.dsh overlay)
dsh --config <path> TUI, alternate tree (demos/tests only)
dsh --resume <id> TUI, resume a session
dsh -p "task" headless one-shot
dsh web [--host --port --dev]
`dsh` is the product front door with no positional; `--config` exists only so
demo:cordis, demo:code-mode, and the keyless PTY smokes can point the shipped
bin at an example tree. Those three sites and the /resume re-exec argv move to
`--config <path>`. The `-p` + `--config`/`--resume` mode-mixing guard and the
cordis.yml-owns-host/port-default fix are preserved.
Agent Note + Chinese pair, README, tui.ts docs updated. All 13 PTY smokes
(including code-mode via --config and the exec-replace resume handoff) green.