denly CLI reference: enroll a machine, install projects, upgrade

Every denly command in one table: login, install, groups, doctor, start, stop, restart, status, logs, upgrade, whoami, authmode, set-key and logout, on macOS, Windows and Linux.

Command	Purpose
`denly login`	Sign this machine into a workspace.
`denly install <project>`	Clone a Git repo or create a no-Git folder at `~/Denly/<project-id>`, then enroll, start, and verify it.
`denly install <project> --path <folder>`	Adopt an existing Git checkout, or create/adopt that exact no-Git folder.
`denly install --group <group>`	Install every project assigned to a group runner.
`denly groups`	List available project groups.
`denly doctor`	Check platform, service, credentials, runtimes, and connectivity.
`denly start\|stop\|restart --all`	Apply a lifecycle action to all installed runners.
`denly projects\|status\|logs`	Inspect local and cloud state. `--all` works on `status`, not on `logs`.
`denly install-all`	Install every project this machine can reach, in one pass.
`denly install <project> --dir <parent>`	Clone into a parent directory instead of naming the folder itself. Mutually exclusive with `--path`.
`denly whoami`	Which account and workspace this machine is signed into.
`denly authmode`	How each installed agent CLI is authenticated here.
`denly set-key` / `clear-key`	Store or remove an API key in the machine's own secret store.
`denly logout`	Sign this machine out. Installed runners stop being able to claim.
`denly doctor --all\|--runtime <id>\|--no-probe`	Check every project, one runtime, or skip the network probes.
`denly --version`	The runner build on this machine.

Add --json to projects, groups or whoami for machine-readable output.