chore: version the package for v0.3.0

[michealroberts]

What This Changes

• Versions @observerly/orderly from 0.2.0 to 0.3.0, applying the eight changesets accumulated on main since v0.2.0: six minor changes and two empty ones for documentation.
• Writes the 0.3.0 section of CHANGELOG.md with one linked entry per change: the QueueBody type (feat(queues): add the QueueBody type to the queues module in @observerly/orderly #66), the at option on send() (feat(queues): add an at option to send() in the queues module in @observerly/orderly #64) and sendBatch() (feat(queues): add the at option to sendBatch() in the queues module in @observerly/orderly #65), sunrise() (feat(schedules): add sunrise() for the sunrises seen from a place on Earth in @observerly/orderly #69), sunset() (feat(schedules): add sunset() for the sunsets seen from a place on Earth in @observerly/orderly #70), and @observerly/astrometry as the one runtime dependency (chore(dependencies): add @observerly/astrometry as the one runtime dependency in @observerly/orderly #68).
• Removes the consumed changeset files.

Notes For Reviewers

• Merging this does not publish. Tagging the merged commit v0.3.0 on main runs the release workflow, as RELEASING.md describes.
• pnpm changeset:version with the configured changelog-github generator fails from this environment, since GitHub's GraphQL API rejects the available token with a 401. The entries were generated with the default generator and rewritten into the changelog-github shape, each commit mapped to the pull request that merged it through the first-parent history of main. The changeset configuration is unchanged.
• No source changes. The full gate chain is green on the versioned tree and the built package reports 0.3.0.

Checklist

• Tests cover the change, and run inside workerd
• A changeset is included, or the change is not one a consumer would notice
• No Node built-ins were introduced