Add durable workflow triggers and waits

docs/CONCEPT.md

@@ -116,18 +116,22 @@ The first executable slice now provides:
 - an operator dialog for starting, inspecting, and advancing instances
 - an owner-side Service launcher that starts an authorized active definition,
   retains the exact Service/binding provenance, and safely replays Portal calls
+- activation-bound API, one-time/interval schedule, platform-event, and
+  parent-workflow trigger registrations with exact-revision dispatch
+- durable duration/deadline/event wait subscriptions and scale-out-safe claims
+- a separate transactional platform-event consumer with bounded JSON filters
+  and variable mappings, idempotent delivery, and current-authority rechecks
 
-The next execution slices should provide:
+The next execution depth should provide:
 
 - static workflow definition registration from configuration packages
-- event, API, schedule, and parent-workflow start dispatchers
 - guard hooks implemented through capability calls
 - registry-driven generic module-action execution records
 - action/effect previews for transitions that call other modules
 - explicit blocked, retryable, quarantined, manual-required, and
   compensation-required states
 - dashboard summary provider
-- event emission and audit integration
+- cron/calendar scheduling through a governed scheduler adapter
 
 ## Permissions
 
@@ -165,11 +169,13 @@ Current tables:
 - `workflow_instances`
 - `workflow_instance_steps`
 - `workflow_instance_events`
+- `workflow_triggers`
+- `workflow_trigger_deliveries`
+- `workflow_wait_states`
 
-Future generic action execution and timers may add:
+Future generic action execution may add:
 
 - `workflow_command_records`
-- `workflow_timers`
 
 Definitions should be immutable by version after activation. Instances should
 reference the exact version used at start.
@@ -196,8 +202,11 @@ Minimum tests:
 - events are emitted for start/transition/completion
 - configuration package can install a simple workflow definition
 
-## Open Decisions
+## Bounded Decisions
 
-- Whether long-running timers use Celery beat, a module scheduler, or an ops
-  scheduler abstraction.
-- How workflow variables are redacted and retained.
+- Native scheduling deliberately supports one-time and minimum-60-second
+  interval triggers. Cron/calendar semantics belong to a future governed
+  scheduler adapter rather than an unbounded expression evaluator in Engine.
+- Platform events contain sanitized lifecycle context, not raw instance
+  variables. Definition mappings can select only bounded event fields; broader
+  variable retention/redaction remains policy-controlled product depth.