chore(release): prepare 0.3.0

The [Unreleased] section becomes [0.3.0] - unreleased; the date becomes real
on the day it is tagged. It gains a one-paragraph summary pointing at the
schema bump, because that is the only change in the release that asks
anything of a consumer and it would otherwise be the fourth item under the
third heading.

A minor rather than a patch this time: `baseUrl` accepts a function
(additive public API), `limits` gained `teardownTimeoutMs`, and the report
schema moved to 3. Versions in both packages and the CLI's pin were already
0.3.0 from when 0.2.1 was cut, and the release guard confirms all three agree
with the changelog.

The release-day script in the home directory is retargeted at 0.3.0 and
gains a second edit: the README's 0.3 roadmap row goes from "implemented,
release pending" to "released" - on the day, because a row is marked
released only once the release exists.

Verified at 0.3.0: typecheck (now including the tests), 192 tests, the
packaged-install check, the release guard against v0.3.0, typedoc, and the
same on Linux from a clean clone.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: MasterplaYCoding

CHANGELOG.md

@@ -5,7 +5,13 @@ All notable changes are recorded here. This project follows
 versioning. Until `1.0`, the public API and the report schema may change
 between minor versions; each change will be listed here with a migration note.
 
-## [Unreleased]
+## [0.3.0] - unreleased
+
+The date becomes real on the day it is tagged; see [RELEASING.md](RELEASING.md).
+
+Restarting the application under test mid-scenario, bounded teardown, and
+report schema `3` — the one change here that needs a consumer's attention; see
+*Changed* for the migration line.
 
 ### Added