feat(cli): add wspc tour command

[yurenju]

Adds a handwritten wspc tour command that fetches the guided-tour script and prints it for the agent to follow.

Behavior

• Fetches https://mcp.wspc.ai/guide (public, unauthenticated; overridable via WSPC_GUIDE_URL for local dev), then prints the script to stdout.
• TTY-gated hint: in an interactive terminal it writes a one-line note to stderr reminding you the script is for your AI agent; when piped/captured by an agent it prints only the script on stdout, so nothing pollutes the agent's context.
• Errors surface cleanly via the existing top-level dispatch catch (error: tour_fetch_failed: <status>, exit 1).

Pairs with

The /guide endpoint and guide_start MCP tool are in the wspc monorepo (separate PR). This command consumes the same WSPC_GUIDE text over HTTP, so there is a single source of truth.

Test plan

• npm test -- tour cli-root — 6 passing (resolveGuideUrl default/override, fetchGuide 200/non-2xx, wspc --help lists tour).
• npm run typecheck — clean.
• Manually verified against a local /guide: piped run prints only the script (no hint on stdout).