Tasks: wait on the outcome, and make the shape findable

A DAG, not a list. Task 1 is the red root: it is what makes tasks 2 and 3 provable, so it lands first even though it is the newest code here.

flowchart LR
    T1["1 — --dispatch-lag<br/>(the red root)"] --> T2["2 — fix the webhook test"]
    T1 --> T3["3 — fix the poller test"]
    T2 --> T4["4 — the rule in reference/testing.md"]
    T3 --> T4
    T4 --> T5["5 — capability doc + decision-091"]
    T2 --> T6["6 — verification: lagged + clean suite, evidence"]
    T3 --> T6
    T5 --> T7["7 — execution log, PR briefing"]
    T6 --> T7

• [x] 1. pytest --dispatch-lag=<seconds> — pytest_addoption plus an autouse fixture in cli/tests/conftest.py that delays every dispatcher write following a spawn or a delivery. Inert (one comparison) at the default. Requirements: R2.1, R2.2 Test: T9a — the two named tests must fail under it before anything is fixed.

• [x] 2. test_delivery_error_is_isolated_and_redelivery_retries waits for the release — wait on "e-1" not in server_factory.dispatcher.deduper; drop the time.sleep(0.2); add the ServerFactory.dispatcher accessor the wait needs. Requirements: R1.1, R1.2, R1.3 Test: T2, T9b

• [x] 3. test_an_abandoned_comment_is_reported_on_the_work_item waits for the outcome — wait on dispatcher.delivery_status("poll-comment-IC_2", [REF]) == "unhandled", the same call the next poll cycle makes. Requirements: R1.1, R1.2, R1.3 Test: T2, T9b

• [x] 4. The rule in skills/the-loop/reference/testing.md — a RULE section: wait on the state you depend on, never on a signal that precedes it; the attempt/outcome distinction; --dispatch-lag as the way to check. Requirements: R3.1, R2.3 Test: T13

• [x] 5. Capability doc and decision — docs/capabilities/testing-and-contracts.md current behaviour + history row; docs/decisions/decision-091.md and the index row. Requirements: R3.2 Test: T13

• [x] 6. Verification — the lagged suite (before and after), the clean suite, lint, format, typecheck; evidence committed under evidence/. Requirements: R1.4, R2.2 Test: T2, T8, T9, T13

• [x] 7. Paper trail — execution-log.md (phases, progress, capability docs, documentation), the reviewer briefing on the PR, phase label kept in sync. Requirements: the loop's own rules Test: n/a — reviewed, not executed.