fix(storage): route every file op through getStorageBackend()

Removes 12 direct minioClient.{put,get,remove}Object call sites that
bypassed the pluggable storage abstraction.  Filesystem-mode deploys
(MULTI_NODE_DEPLOYMENT=false, storage_backend=filesystem) silently
broke at every site: GDPR export, invoice PDF, EOI generation, portal
download, file upload, folder create/rename/delete, signed PDF land,
maintenance cleanup, etc.  Each site now resolves the active backend
and uses its put/get/delete + the new presignDownloadUrl() helper.

Folder marker objects in /files/folders/* keep the same on-the-wire
shape but route through the backend.  A future refactor should move
folder bookkeeping to a DB-backed virtual-folder table (see audit
HIGH §3 follow-up note in the route file).

Sites left untouched: src/lib/services/system-monitoring.service.ts
and src/app/api/ready/route.ts use minioClient.bucketExists as an S3-
specific health probe — those are correctly mode-aware and stay.

Refs: docs/audit-comprehensive-2026-05-05.md HIGH §3 (auditor-D Issue 1)

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

src/lib/services/portal.service.ts

@@ -11,7 +11,7 @@ import { ports } from '@/lib/db/schema/ports';
 import { yachts } from '@/lib/db/schema/yachts';
 import { companies, companyMemberships } from '@/lib/db/schema/companies';
 import { berthReservations } from '@/lib/db/schema/reservations';
-import { getPresignedUrl } from '@/lib/minio';
+import { presignDownloadUrl } from '@/lib/storage';
 import { getCountryName } from '@/lib/i18n/countries';
 
 // ─── Dashboard ────────────────────────────────────────────────────────────────
@@ -301,7 +301,7 @@ export async function getDocumentDownloadUrl(
 
   if (!file) return null;
 
-  return getPresignedUrl(file.storagePath);
+  return presignDownloadUrl(file.storagePath);
 }
 
 // ─── Yachts (direct + via company) ────────────────────────────────────────────