Initial commit: Add project files

db/migrations/0013_execution_readiness_building_blocks.sql

@@ -0,0 +1,68 @@
+-- v12.1 execution-readiness delta. Prior migrations remain immutable.
+
+alter table building_blocks.outbox_message
+    add column if not exists next_attempt_at timestamptz null,
+    add column if not exists lease_owner text null,
+    add column if not exists lease_until timestamptz null,
+    add column if not exists dead_lettered_at timestamptz null,
+    add column if not exists last_error_code text null;
+
+create index if not exists ix_outbox_dispatchable
+    on building_blocks.outbox_message (coalesce(next_attempt_at, occurred_at), occurred_at, message_id)
+    where published_at is null and dead_lettered_at is null;
+
+alter table building_blocks.inbox_message
+    add column if not exists processed_at timestamptz null,
+    add column if not exists result_hash text null;
+
+create table if not exists building_blocks.projection_checkpoint (
+    projection_name text not null,
+    projection_version integer not null check (projection_version > 0),
+    source_watermark text not null,
+    last_event_id uuid null,
+    content_hash text not null,
+    built_at timestamptz not null,
+    primary key (projection_name, projection_version)
+);
+
+create table if not exists building_blocks.projection_rebuild_run (
+    rebuild_id uuid primary key,
+    projection_name text not null,
+    target_version integer not null check (target_version > 0),
+    through_watermark text not null,
+    dry_run boolean not null,
+    requested_by text not null,
+    requested_at timestamptz not null,
+    status text not null,
+    source_count bigint null,
+    projected_count bigint null,
+    result_hash text null,
+    finished_at timestamptz null,
+    error_code text null
+);
+
+create table if not exists building_blocks.audit_event (
+    audit_event_id uuid primary key,
+    entity_type text not null,
+    entity_id text not null,
+    event_type text not null,
+    actor_id text not null,
+    correlation_id text not null,
+    payload_json jsonb not null,
+    payload_hash text not null,
+    corrects_audit_event_id uuid null references building_blocks.audit_event(audit_event_id),
+    occurred_at timestamptz not null,
+    unique (entity_type, entity_id, event_type, payload_hash)
+);
+
+create or replace function building_blocks.prevent_append_only_change()
+returns trigger language plpgsql as $$
+begin
+  raise exception 'append-only row cannot be updated or deleted';
+end;
+$$;
+
+drop trigger if exists audit_event_append_only on building_blocks.audit_event;
+create trigger audit_event_append_only
+before update or delete on building_blocks.audit_event
+for each row execute function building_blocks.prevent_append_only_change();