Task-005: Add a zero-build 60-second tour

[rsasaki0109]

Linked task

Task-005

Summary

• Add zero-build Bash and PowerShell quick-start launchers.
• Validate the complete generated review bundle before opening it.
• Put a one-line 60-second tour at the top of the README onboarding path.
• Run the headless quick-start check in Design Review on every PR.

Implementation notes

The tour opens the committed review generated from the real bracket Design Graph and DesignPatch. It does not download or execute a MusubiCAD binary, contact the network after cloning, or mutate a document. The existing Rust command remains clearly separated as the full executable workflow.

Tests added

• ./quickstart.sh --check in GitHub Actions
• Bash syntax and asset-completeness validation
• PowerShell asset-completeness validation
• HTML title identity check in both launchers

Validation

• PowerShell check: 182 ms
• Bash check: 287 ms
• GitHub GFM rendered anchor resolves to the 60-second section
• All local README HTML asset targets exist

Docs updated

• README call to action, zero-build tour, executable workflow distinction, and roadmap

Known limitations

The tour is intentionally read-only. Regenerating or editing the design still requires the Rust CLI build until downloadable binaries are published.