disconnectlisted

`/pad:disconnect` withdraws THIS session's consent to receive `pad push` notifications. It holds for the rest of the session even if the repo opted in via `.pad.toml push.auto_arm` — a disconnect must not be a lie. If the `pad` CLI is missing (command not found), say so and point at https://getpad.dev/install. Otherwise ALWAYS run the disarm — do NOT gate it on finding a `.pad.toml`. Consent is scoped to this SESSION (keyed by the session, not the workspace), so a session that connected in one repo must be able to disconnect from anywhere, including a directory with no linked workspace; refusing to disarm there would leave it receiving pushes. Steps: 1. Run `pad session disarm`. This writes a session-scoped explicit-off marker (it does not delete config), so the session stops accepting pushes now and stays that way for its remaining life. It works regardless of the current directory's workspace. 2. Tell the user they're disconnected. If the command reported that the repo has `auto_arm` on, add the honest caveat: this session is disconnected, but a NEW session in this repo will connect again — to turn that off permanently, remove `push.auto_arm` from `.pad.toml` (the same deliberate edit that turned it on). Note: the monitor re-checks consent every couple of seconds and drops the open stream when it sees the disarm, so delivery stops within a brief window rather than lingering. Run `/pad:status` to confirm the state.