Publish Buzz for Devin source alpha.8

[fenner888]

Summary

• point the public README and builder guide at the immutable alpha.8 tag
• use release-specific alpha.8 clone and local branch names
• apply Block upstream's lockfile-only nostr 0.44.6 security update to the root and separately locked desktop crate

Release contents

Alpha.8 includes the merged explicit agent-harness onboarding update from #12. New users can choose the bundled Buzz Agent for Fizz, Honey, and Bumble instead of silently inheriting Devin. Existing saved defaults are preserved.

The dependency update matches Block upstream commit 31e2de196 and resolves the newly enforced malformed NIP-04 IV remote-denial-of-service advisory without suppressing it.

Validation

• GIT_CONFIG_GLOBAL=/dev/null cargo deny check advisories — advisories OK
• cargo test -p buzz-core — 229 unit + 2 doc tests passed
• git diff --check
• confirmed no alpha.7 references remain in the current public installation instructions
• behavior PR Require an explicit default agent harness #12 passed Desktop Core, macOS build, four smoke shards, and both integration shards before merge

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.