feat(audit): wider coverage — sensitive views, cron, jobs, portal abuse

Builds on the audit infra split (severity/source) by emitting events
from every place a security or operations review would want to see:

Sensitive data views (severity=warning):
- GDPR export download URL issued
- Audit log page opened (watch-the-watchers; first page only)
- CSV export of expenses
- Webhook secret regenerated

Authentication abuse (severity=warning, source=auth):
- Portal sign-in: success + failed-credentials + portal-disabled
- Portal password reset: unknown email + portal-disabled + bad token
- Portal activation: bad/expired token

Inbound webhook hardening:
- Documenso webhook with invalid X-Documenso-Secret now writes
  webhook_failed instead of being silently logged

Background work (source=cron / job):
- New attachWorkerAudit() helper wires every BullMQ worker to emit
  job_failed (severity=error) on .on('failed') and cron_run on
  .on('completed') for any job whose name matches the recurring
  scheduler list. Applied across all 10 workers.

1175/1175 vitest passing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/api/v1/admin/audit/route.ts

@@ -8,6 +8,7 @@ import { searchAuditLogs } from '@/lib/services/audit-search.service';
 import { db } from '@/lib/db';
 import { user } from '@/lib/db/schema/users';
 import { errorResponse } from '@/lib/errors';
+import { createAuditLog } from '@/lib/audit';
 
 const auditQuerySchema = z.object({
   limit: z.coerce.number().int().min(1).max(200).default(50),
@@ -67,6 +68,34 @@ export const GET = withAuth(
         actor: r.userId ? (userMap.get(r.userId) ?? null) : null,
       }));
 
+      // Watch-the-watchers: record that an operator opened the audit log
+      // page. Only fire on the first page (no cursor) so paginating
+      // through doesn't spam the log; use 'view' at warning severity so
+      // the entry stands out in the inspector.
+      if (!cursor) {
+        void createAuditLog({
+          userId: ctx.userId,
+          portId: ctx.portId,
+          action: 'view',
+          entityType: 'audit_log',
+          entityId: 'list',
+          metadata: {
+            filters: {
+              entityType: query.entityType,
+              action: query.action,
+              severity: query.severity,
+              source: query.source,
+              userId: query.userId,
+              entityId: query.entityId,
+              search: query.search,
+            },
+          },
+          ipAddress: ctx.ipAddress,
+          userAgent: ctx.userAgent,
+          severity: 'warning',
+        });
+      }
+
       return NextResponse.json({
         data,
         pagination: {