Release automatically on every feat and fix instead of waiting on a hand-merged release PR #21

Raised by @GauranshMathur in a Claude Code session: each feat or fix merged to main should bump the version and publish a release, without anyone merging the release PR by hand.

Today

release-please gathers merged commits into one standing release PR (#15 was the latest). The version bump, tag and GitHub release happen only when someone merges that PR, so releases wait until it is noticed.

Decisions made

• After release-please creates or updates its release PR, the same workflow job merges it with gh pr merge --squash.
• That merge is made with GITHUB_TOKEN. GitHub does not start new workflow runs for events made by that token, as release-please-action's README notes, so the push would not run release-please again to tag the release. A second release-please step in the same job, right after the merge, tags the release and publishes it. If that step ever misses the merged PR, the next push to main tags it, because release-please releases any merged PR still labelled autorelease: pending.
• The release PR gets no CI run, again because GITHUB_TOKEN events start no workflows. That is accepted: it changes only version strings and CHANGELOG.md, and every commit it releases passed CI in its own PR.
• Commits that are not releasable, such as docs and ci, open no release PR, so the new steps are skipped for them.
• The README's Development section is updated to describe the new flow.

Facts checked

• .github/workflows/release-please.yml already has contents: write and pull-requests: write, which merging needs.
• chore(main): release 0.3.0 #15 had no required checks blocking a merge (mergeable_state: unstable, not blocked).
• release-please-action v4 exposes a pr output, a JSON PullRequest object that includes number, and leaves it unset when no PR was created or updated.