Non-disableable default handler for built-in state reconciliation.

Runs first in the dispatch chain before any user-registered handlers. Cannot be removed or reordered by configuration.

Behaviour

Reconciles Stripe webhook families covering subscription, invoice, charge, refund, and payment method state. Each reducer:

1. Derives evt_ts from the raw event created unix timestamp.
2. Loads the local row by processor id.
3. Skip stale: if row.last_stripe_event_ts != nil and evt_ts is strictly less than it, emit [:accrue, :webhooks, :stale_event] telemetry and return {:ok, :stale} without calling the processor. Timestamp ties (:eq) still proceed.
4. Refetch canonical: always call Accrue.Processor.fetch/2 to pull the current object — never trust the payload snapshot alone.
5. Project via the appropriate *Projection.decompose/1 (or schema-specific upsert) and write via the webhook-path changeset (Invoice.force_status_changeset/2 where a legal transition bypass is required).
6. Stamp last_stripe_event_ts / last_stripe_event_id on the row so the next out-of-order event can skip.
7. Record an accrue_events row in the same Repo.transact/1.

Entry points

• handle/1 — accepts the raw event map (both string- and atom-keyed shapes). Used by Accrue.Processor.Fake.synthesize_event/3 for in-process test dispatch.
• handle_event/3 — the Accrue.Webhook.Handler behaviour entry point invoked by Accrue.Webhook.DispatchWorker. Dispatches via the existing %Accrue.Webhook.Event{} struct (object_id + created_at + type) to the shared reducer.