feat: added a new test scenario: boot-outside-repeat-window

[michal-skraburski]

Summary

This PR adds the requested boot-outside-repeat-window scenario to solidify the boot looping window and protect against regression where the boot loop window may tighten.

Related Issue

#174
Closes #174

Changes

• Created boot-outside-repeat-window scenario and populated it.
• Inserted the boot-outside-repeat-window scenario into the exports of tests/index.ts
• Incremented the tests specifying scenario array length, also updated the exact-match name scenario testing against additions to the scenario exports.
• Added a plain changeset using pnpm changeset.

Checklist

• [ x] Tests added or updated for the behavior this PR introduces
• [ x] Lint passes (pnpm lint)
• [ x] Typecheck passes (pnpm typecheck)
• [ x] Tests pass (pnpm test)
• [ x] Build passes (pnpm build)
• [ x] Changeset added (if changing publishable package behavior)
• CURRENT_STATE.md updated (if applicable)
• AGENTS.md updated (if architecture or build commands changed)
• No secrets or sensitive data in committed artifacts
• Untrusted-input handling reviewed (if touching parsing, CLI, or UI)

Notes for Reviewer

[sepehr-safari]

Welcome, and thanks for this. The scenario is correct and I have tidied the branch
around it.

I ran your trace through the engine and it reports nothing, which is what this
scenario needs to do. The two boots are 390 seconds apart against a 300 second
window, so they are outside it with real margin rather than sitting on the
boundary, and the heartbeats keep the heartbeat rules quiet. CS-SYNTHETIC-023 is
the reserved ID and the changeset is patch. All of that was right.

Two things needed fixing, and one of them was a genuine build break rather than a
nit.

The scenario count lives in four places, and the branch updated one. You moved
packages/toolkit/src/scenarios/index.test.ts, but tests/external-fixture/test.mjs,
README.md and packages/toolkit/README.md all state it too. The external fixture
test asserts the number, so it failed outright:

FAIL: 21 scenarios exported (got 22)

Only the registry test and the external fixture test fail when they drift; the two
READMEs go stale silently, which is what makes them easy to miss. The list is in
How to Add a Scenario,
and I have flagged that the issue text could call it out harder.

Prettier. Two files needed pnpm format. Run it from the repo rather than an
editor integration, since the repo config is what CI checks first.

I pushed both fixes to your branch along with a merge of current main, which had
moved on to 22 scenarios in the meantime, so the count is now 23. Your scenario file
and changeset are untouched.

One process note that is on me, not you: your first CI run sat waiting for three
days rather than failing. GitHub holds workflow runs from first-time contributors
until a maintainer approves them, so that was pending on me. It is approved and
both jobs pass. Once this merges you will not hit that wait again.

Merging. Thanks for picking up a good-first-issue cold and getting the substance
right first time.