Tests the three flow patterns composed

[johnnyt]

What

One new test module, test/statifier_blocks/flow_patterns_composed_test.exs, and one fixture, test/fixtures/documents/flow_patterns/composed.json, compose the three documents docs/guides/flow-patterns.md shows one by one:

• a core.parallel of optional arms (complete: "all"), each lane guarded by its own one-arm core.branch;
• in the confirm lane, the bounded step: a core.group carrying the deadline recipe (a delayed core.send at the head of the body, a core.on_event with outcome abandon on the rail) around a core.await;
• in the shelf lane, the park: a core.group whose body is one core.wait and whose rail carries two abandoning handlers.

The world is the guide's library hold: a hold is placed, the desk may be asked to confirm it within a day, the item may wait on the hold shelf for seven days, and the hold is closed when both lanes are done.

What the test asserts

• Publish.findings/3 reports no error finding, the compile succeeds with no warning, and the engine parses the chart.
• Each pattern's timer and interrupt lines in the compiled chart are the guide's own lines byte for byte (each one is also asserted on the page), found inside that pattern's own group, and each group inside its own lane; the optional-arm lines carry this document's lanes and guards.
• Run with both lanes asked, each lane arms its own timer; at the one-day bound the confirm lane finishes and cancels its timer while the shelf lane stays parked; a collection then closes the hold. Run with only the confirm lane asked, only its timer is armed and the bound alone closes the hold. Run with neither asked, the hold closes at once with no timer.
• Describe names every arm (both guards, both otherwise arms, every handler), and the Map titles both lanes and draws every interrupt edge and the one timer edge.

The deadline-handler sabotage

The acceptance first asked that dropping the deadline handler make a finding appear. It does not, and the clause now reads "drop the deadline handler: the compiled chart's interrupt-transition assertion goes red" (ruled by the operator, 2026-10-09): the sabotage turns the interrupt-transition assertion red; no Publish finding exists for a dropped deadline handler. With the handler dropped, Publish.findings/3 returns no finding and the compile no warning; what goes red is the compiled-chart test (the deadline's interrupt transition), the two run tests that ask for the confirm lane (the handler is no longer armed) and the Describe test (the handler's line). The note above the compiled-chart test records this. No file under lib/ changes.

Sabotage, one row per check

Mutation	Went red
Fixture: deadline handler dropped from the confirm group's rail	compiled-chart, both confirm-lane run tests and Describe test, on assertions; the Publish test stayed green
Fixture: the parallel's complete set to "every"	Publish test, on the error-finding assertion
Cancels.onexit: no cancel emitted	run (both asked) test on the cancelled-timer assertion; compiled-chart test on the onexit line
Fixture: the shelf branch's condition set to true	run (neither asked) test; compiled-chart and Describe tests
Fixture: the lane shelf renamed rack	Describe test, on the Map's lane titles; compiled-chart test
Fixture: the two branches' conditions swapped	run (only the confirm lane asked) test, on the armed timers; compiled-chart test
Fixture: the deadline's send moved out of the group, ahead of it in the branch arm	compiled-chart test, on the send being inside the group; Describe test

Each mutation was restored from a copy and checked byte-equal before the next.

Review and gate

No contract surface and no file under lib/ changes; the test module itself is just over 300 lines, so the review tier is the conductor's call. The pre-request review round ran in-turn before this request opened, and its accepted points are in this commit: each pattern's lines are asserted inside their own group and lane, and a one-lane run was added.

Gate: full mix quality green on the committed tree (3,960 of 3,960 tests, 95.3% coverage, dialyzer clean, ADR cites green). No changelog fragment: changelog.d/README.md excludes test harness and fixtures.

The ADR-0002 typed-send Note does not ride this request: the reference host's typed-send step had not moved to lib/ when this request was written. It has since moved, so whether that Note's pointer needs a dated Note of its own is a follow-up for this repo.