feat(compose): sequence separately recorded Flow bundles

[abrichr]

Summary

openadapt-flow compose sequences already-compiled child bundles under a handoff contract. Each child stays bound to the surface it was recorded on. certify and run execute the parent directory; replay refuses it.

openadapt-flow compose \
  --child intake=./intake-bundle \
  --child posting=./posting-bundle \
  --handoff intake.patient_id=posting.patient_id \
  --out composed
openadapt-flow certify composed --policy clinical-write
openadapt-flow run composed --config deploy.yaml

The launcher form is openadapt flow compose.

Child B starts only after child A ends VERIFIED, or a halt class named with --allow-halt. Handoffs copy parameter values that A's confirmed effect contract already bound. Window titles and URLs are not evidence. Missing evidence HALTs.

Default order is --child order. --after NAME=PRED declares a DAG; cycles refuse at authoring. The parent artifact is composition.json plus copied children, not a larger ProgramGraph.

Child execution goes through execute(capability, admission, inputs, ...) in openadapt_flow/runtime/composition.py. Today that binds to governed run (admission gate plus Replayer). When a public execute() primitive lands, rebind there. Raw replay is not the public path.

Rebased onto main after #432. openadapt_flow/compiler/__init__.py and docs/design/WORKFLOW_PROGRAM_IR.md carry both the REST-admission exports and the compose sequencer.

What this does not do

• No process contract, and no new workflow-program IR (StateKind, subflow, worklist) on the parent.
• No backend switch inside one recording. Compose will not retarget a child onto a surface it was not recorded on.
• No Production admission or live Citrix claim. Evidence is unit tests plus a two-child fixture whose second child is a local FakeBackend.

What a reviewer must check

• Fail-closed handoffs: a missing or empty effect-bound fact HALTs before the next child starts. tests/test_compose_runtime.py covers missing evidence, unverified predecessor, and allowed halt class.
• Compose is a sequencer of admitted child bundles, not a second orchestrator and not an IR enlargement. Confirm openadapt_flow/composition.py stays a parent spec plus copied children.
• replay refuses a composition directory; only certify / run execute it.
• compiler/__init__.py exports both author_composition and the REST admission symbols from feat(compiler): admit REST bindings only after held-out Effect confirmation #432.

Test plan

• tests/test_compose_authoring.py — copy, effect-bound source, unknown target, one child, cycle, backwards handoff, explicit --after
• tests/test_compose_runtime.py — missing handoff HALT, unverified predecessor HALT, allowed halt class, scripted VERIFIED handoff, MockMed + FakeBackend fixture
• tests/test_cli_compose.py — parser, CLI write, replay refusal
• ruff + mypy on the new modules
• CI test job passed on 32722d8 (38m9s), binding the three compose test files for compose-recorded-bundles

[abrichr]

Merged by an agent session, not the founder.