feat(core-shared): grace-purge soft-deleted rows + boot registration

The retention purge job gated its whole body on activeRetention while
every collection declares only postDeletion, and no app ever called
registerRetentionPurgeJobs — retention was dead end to end (audit
findings A2 + A3). The DSR soft delete now stamps a deletedAt tombstone
on postDeletion collections (kept distinct from processingRestrictedAt
so an Art. 18 restriction never feeds the purge), the job grace-purges
tombstoned rows past postDeletion.duration with the declared action,
core-cms injects the tombstone field + Payload task definitions, and
bindAllProduction enqueues the first purge cycle at boot.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

apps/web-next/src/server/bind-production.ts

@@ -21,6 +21,10 @@ import {
   NoopRateLimit,
   type RateLimitBudget,
 } from "@repo/core-shared/rate-limit";
+import {
+  registerRetentionPurgeJobs,
+  type GetPayloadFn,
+} from "@repo/core-shared/payload";
 import { bindAudit, type IAuditLog } from "@repo/core-audit";
 import {
   bindProductionConsent,
@@ -192,6 +196,17 @@ export async function bindAllProduction(): Promise<void> {
   bindProductionMarketingPages(ctx);
   bindProductionNavigation(ctx);
   bindProductionMedia(ctx);
+
+  // Kick off the retention purge cycle (audit finding A3): enqueue the first
+  // `retention-purge--<slug>` job for every collection declaring a
+  // custom.retention.purgeSchedule. The task definitions live in the Payload
+  // config (core-cms jobs.tasks); each run re-enqueues the next cycle.
+  await registerRetentionPurgeJobs({
+    queue,
+    config: resolvedConfig,
+    getPayload: getPayload as unknown as GetPayloadFn,
+    auditLog,
+  });
 }
 
 /**