spawn-claude-workspacelisted

# Spawn autonomous coding workspace Spawn an autonomous coding agent in a new cmux workspace without taking focus. Use the `cmux-workspace` skill's targeting rules: always target explicit workspace/surface refs, use RPC parameter `surface_id`, and never call focus-changing commands. Two engines are supported, selected by the `engine` input: - **`droid`** (default) — Factory Droid on GLM-5.2. The historical behavior; unchanged. - **`claude`** — Claude Code via the login-shell `claude` alias. Use when the task requires a Claude-only capability, most importantly a Claude Code plugin skill such as `/architect-ffp:archffp` (Droid cannot run Claude plugins). ## Invariants (both engines) - Always pass `--focus false` to `cmux new-workspace`. - Never stream a long prompt through cmux. Stage it under `~/.assistant/spawn-prompts/` and send a short `Read <path>...` instruction. - Use `surface.send_text` followed by an explicit `surface.send_key` Enter. - Never select the new workspace automatically. - The transcript is the authoritative submission signal — a cmux success response alone is NOT confirmation. ## Workspace name suffix and sidebar color — NOT owned here Do not set a `[N]` name suffix or a sidebar color in this skill. The `cmux-ws-numberer` daemon (`bin/cmux-ws-numberer.py`, a launchd job) owns both: it polls every ~3s and appends the `[N]` ref suffix plus a distinct palette color to every workspace that lacks one. Leave naming and color to the daemon. ## Engine-speci