[RFC]: Add script/workflow/action to announce office hours to Bluesky

[kgryte]

The basic idea would be to run a weekly cron job which checks whether an office hours issue is open for the upcoming week. If present, the cron would post a message to Bluesky announcing the office hours with a link to the relevant issue.

If an issue does not exist for the current week, the cron does nothing.

Notes

• Given office hours on Tuesday, we'd want this to go out on Monday. We could (potentially) post a follow-up reply the day of, or do something which signal boosts.
• This puts the onus on us to ensure we are closing the previous week's issue and adding a new issue with updated info.
• In order to facilitate automation, we may need to embed YAML frontmatter in the issue, such as the date and time, in order to avoid needing to perform freeform text parsing.