CHANGELOG's Unreleased section doesn't reflect the single-resource additions merged since #166

CHANGELOG.md's [Unreleased] > Added section stops at a batch entry listing resources that closed #122-#166. Since then, a long run of individual one-resource-per-PR commits has merged (roughly #168 through the low #200s, judging by recent `git log`), none of which are reflected in the changelog. This isn't urgent (CONTRIBUTING.md only requires a changelog note for *removals*, not additions), but the Added section is now stale enough that it undersells how much the list has grown, and it makes the next release's changelog entry a much bigger reconciliation job than if it were kept current in smaller batches. Decide on a cadence (e.g., a periodic batch update, or a small script/CI check similar to update-counts.mjs) for keeping CHANGELOG.md's Added section in sync with merged single-resource PRs, and catch it up to the current state of README.md.