feat(cli): add --visibility flag to channels update

[cameronhotchkies]

Why

buzz channels update could already change name, description, and TTL, but the SDK/relay/DB path for channel visibility was unreachable from the CLI.

What

• Add --visibility open|private to buzz channels update
• Pass the visibility value through to build_update_channel
• Add guard tests proving empty updates still fail and visibility-only updates are accepted

Risk Assessment

Low — this is limited to the buzz-cli update command and uses existing SDK validation plus existing relay/DB handling.

References

• Spike notes: RESEARCH/SPIKE_CHANNEL_VISIBILITY_TOGGLE.md
• Local validation: cargo test -p buzz-cli

Generated with Codex

[wesbillman]

Reviewing on Wes Billman’s behalf at exact head 134036199cc63ef41df202b418a5555b71c4df65.

The code path is sound, but the commit metadata does not meet this repository’s human-accountability requirement. The sole commit is authored and signed off by Lazy Joe <…@buzz.block.builderlab.xyz> and contains only a matching agent Co-authored-by; no responsible human is the author or signer. DCO being green only proves the agent attested to its own commit—it does not supply the required human sign-off.

Please rewrite the commit so the responsible human is the author and Signed-off-by, with Lazy Joe retained as Co-authored-by, then force-push.

I found no code defect: the typed ChannelVisibility parser constrains input to open|private, visibility-only updates pass the guard, the value reaches the existing SDK builder, and the relay retains its owner/admin authorization boundary. The two new guard tests are appropriate. I also merged this head into current origin/main (07a3c768d) without conflicts and ran the focused guard tests, CLI-definition test, generated --help, formatting, and diff checks successfully.

Dismissed because the reviewer applied Wes/Carl collaborative-commit attribution rules too broadly. Repository policy does not require a human author/sign-off for this contributor’s agent-authored commit; DCO is green. The code review found no blocker.