GRE-288: Add appliance install and launch quick start

[HeadCase]

Summary

• add executable appliance installation and launch instructions to README
• derive a shell-safe qualified release ID from the checked-out commit
• include service verification and approved browser URLs
• add a deployment regression test for the documented user path

This is the documentation follow-up to merged PR #28.

Verification

• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets --all-features -- -D warnings
• cargo test --workspace --all-targets --all-features
• cargo deny check
• cargo machete
• npm test
• deployment tests: 17 passed
• standards review: no remaining findings
• spec review: no findings

Linear: https://linear.app/headcase/issue/GRE-288/retire-temporary-startup-documentation-after-qualified-appliance