feat(setup-skillx): optional --auto-approve in generated command

[linisme]

Summary

• Before rendering the quick-start block, setup-skillx now asks one yes/no question (default no) about embedding --auto-approve in the generated skillx run command.
• When yes, the rendered command gets the flag and an italic disclaimer line inside the marker pair, so a later run that switches back to the default template cleans the disclaimer along with the flag.
• Safety-relaxing flags (scan-disable, WARN auto-confirm, threshold-lowering) remain off-limits in the generated command — those are reader-side decisions.
• Bumps setup-skillx to 1.3.0; mirrors the prompt into the advertise-your-skill web guide.

Test plan

• cargo run -- scan skills/setup-skillx → PASS
• cargo test --workspace → 499 tests, 0 failed
• Manual walkthrough: task-based example (e.g. examples/skills/name-poem) and skills/setup-skillx itself (conversational) — verify default no produces the plain command and yes produces the opt-in block with disclaimer
• Idempotency regression: re-run on an existing v1.2.0 block with no → no-op; toggle no → yes → no, confirm marker-based replacement leaves no orphan disclaimer line
• Localized README regression: ensure the --auto-approve flag literal stays English while the disclaimer italic line gets localized

[github-actions]

Preview Deployment

This PR has been deployed to Cloudflare Pages:

https://4fd5871e.skillx-web.pages.dev