docs(release): finalize v0.2.0 public bootstrap

[codeforester]

Summary

• replace the pre-publication bootstrap wording with the verified v0.2.0 release asset and checksum
• record the published v0.2.0 BOM identity and consumed Base 1.9.0 inputs
• update the public-install test to fetch and verify the release asset
• mark the v0.2.0 readiness handoff with the downloaded-artifact verification evidence

Validation

• bin/base-demo-release-check v0.2.0
• bin/base-demo-dependencies --check --verify-refs
• bats tests/release_test.bats
• bash tests/public_install_test.sh
• downloaded release assets were independently checksum-verified against the finalized BOM and installer