docs(cloud): Rewrite Deploy your first app as a tutorial

[developerjamiu]

PR 3 of the Cloud IA rollout (#568). Depends on PR 2 (#580) for the Deployments concept link target. PR 1 (#578) shipped the install-page rename this links to.

Summary

• Rewrites cloud_docs/01-getting-started/02-launch.md as a tutorial.
• Walks a first-time Cloud user through scloud launch end to end: prereqs → command → four decision prompts → status tail → open URL → next steps.
• Trims the original wordy intro and prereq list; cuts non-decision prompts to focus on Project ID, Plan, Database, and Pre-deploy hooks.
• Links to the Deployments concept (#580) for ongoing deploy operations and to the Custom domains concept (#581) for the BYOD path.

Verification

Every CLI output claim verified against scloud 0.30.0 source (prompt text, defaults, stage names, URL block, scloud.yaml auto-write). npm run build passes locally.

Test plan

• npm run build passes in CI.
• Navigate to /cloud/getting-started/launch and read top to bottom as a first-time reader.
• Confirm the four decision prompts match what scloud launch actually emits.
• Confirm the scloud deployment show output matches the rendered example.
• Click each cross-link and confirm it resolves: /cloud/getting-started/installation, /cloud/concepts/deployments, /cloud/concepts/custom-domains, /cloud/reference/deployment/deployment-hooks.

Follow-up

Once a Plans and pricing page lands in Cloud docs, link to it from the Plan bullet (currently mentions "1-month free trial; no credit card required" without a destination for details).

🤖 Generated with Claude Code

[Swiftaxe]

LGTM