chore(release): v0.3.1-beta - #21

Release prep per docs/releasing.md. Three files: CHANGELOG.md, pyproject.toml, and the README version badge.

Contents

Everything merged since v0.3.0-beta — PR #20:

• Run manifests are no longer gitignored, and nothing ships at ./manifest.yaml; the manifest that used to sit there is now example_manifest.yaml. .gitignore had listed /manifest.yaml and /manifests/ while a manifest.yaml was also tracked, so the entry was inert and edits to the shipped file staged by default.
• docs/private_mirror_workflow.md — how a team keeps a private copy of this repo that still receives upstream releases, for customers whose fetcher work can't be public.

Version choice

0.3.1-beta — a patch. Called deliberately: nothing in the contract surface moved (no manifest schema change, no CLI command or flag change, no fetcher output change), and the file that stopped shipping was self-described in .gitignore as a local working file with canonical samples in examples/.

Worth noting for the record that there is an observable behavior change, which is why the changelog entry carries an explicit upgrade note rather than relying on the version number to signal it: on a fresh clone, paramify scripts sync without --manifest now resolves an absent manifest and provisions nothing instead of the 13 Datadog fetchers, and paramify run manifest.yaml has no file to run. Remedy is one line — copy example_manifest.yaml over, or pass --manifest.

Not included

pyproject.toml's in-flight textual-image optional dependency (welcome-screen mascot) is deliberately excluded — it's uncommitted TUI work, not part of this release. Only the version line moved.