Persist a recoverable fence before the first consequential local delivery #2200

For an explicitly durable customer-local run on its first linear leg, hold local delivery ownership and persist a delivery-uncertain pause at the final consequential GUI or API boundary. Bind it to the exact run manifest, prior progress and linear cursor. Refuse delivery if ownership or the pause cannot be established. Keep the pause through delivery and acknowledgement until the exact matching result checkpoint is durably committed, then advance without repeating the action.

An unresolved pause may use supported read-only verification of the original effect. Otherwise return a named hold. A standalone API write without a retained API contract and any required baseline stays held. Neither an ordinary resume nor an uncertain-retry approval may resend that attempt. Preserve existing managed, resumed and folded-form guards, and the intentionally non-durable replay path.

Acceptance: use deterministic synthetic interruption points before dispatch, after a fake effect and before the checkpoint, and after the matching result checkpoint commits. Cover linear GUI and standalone API. A live competing continuation must refuse. Assert no dispatch without the fence, no duplicate effect on recovery, and no positive result without verification. Unsupported linear routes hold. Program and subflow cursor recovery and stable CLI idempotency are separate slices.

Refs #1480