fix(audit-tier-2): error-surface hygiene — toastError + CodedError sweep

Two mechanical sweeps closing the audit's HIGH §16 + MED §11 findings:

* 38 client components / 56 toast.error sites converted to
  toastError(err) so the new admin error inspector becomes usable from
  user-reported issues — every failed inline-edit, save, send, archive,
  upload, etc. now carries the request-id + error-code (Copy ID action).
* 26 service files / 62 bare-Error throws converted to CodedError or
  the existing AppError subclasses.  Adds new error codes:
  DOCUMENSO_UPSTREAM_ERROR (502), DOCUMENSO_AUTH_FAILURE (502),
  DOCUMENSO_TIMEOUT (504), OCR_UPSTREAM_ERROR (502),
  IMAP_UPSTREAM_ERROR (502), UMAMI_UPSTREAM_ERROR (502),
  UMAMI_NOT_CONFIGURED (409), and INSERT_RETURNING_EMPTY (500) for
  post-insert returning-empty guards.
* Five vitest assertions updated to match the new user-facing wording
  (client-merge "already been merged", expense/interest "couldn't find
  that …", documenso "signing service didn't respond").

Test status: 1168/1168 vitest, tsc clean.

Refs: docs/audit-comprehensive-2026-05-05.md HIGH §16 (auditor-H Issue 1)
+ MED §11 (auditor-G Issue 1).

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

src/lib/services/brochures.service.ts

@@ -15,7 +15,7 @@ import { and, asc, desc, eq, isNull } from 'drizzle-orm';
 import { db } from '@/lib/db';
 import { brochures, brochureVersions, ports } from '@/lib/db/schema';
 import type { Brochure, BrochureVersion } from '@/lib/db/schema';
-import { ForbiddenError, NotFoundError, ValidationError } from '@/lib/errors';
+import { CodedError, ForbiddenError, NotFoundError, ValidationError } from '@/lib/errors';
 import { getStorageBackend } from '@/lib/storage';
 import { buildStoragePath } from '@/lib/minio';
 import { logger } from '@/lib/logger';
@@ -140,7 +140,10 @@ export async function createBrochure(input: CreateBrochureInput): Promise<Brochu
         createdBy: input.createdBy,
       })
       .returning();
-    if (!row) throw new Error('Failed to create brochure');
+    if (!row)
+      throw new CodedError('INSERT_RETURNING_EMPTY', {
+        internalMessage: 'Failed to create brochure',
+      });
     return row;
   });
 }
@@ -177,7 +180,10 @@ export async function updateBrochure(
       .set(updates)
       .where(eq(brochures.id, brochureId))
       .returning();
-    if (!row) throw new Error('Failed to update brochure');
+    if (!row)
+      throw new CodedError('INSERT_RETURNING_EMPTY', {
+        internalMessage: 'Failed to update brochure',
+      });
     return row;
   });
 }
@@ -276,7 +282,10 @@ export async function registerBrochureVersion(
       uploadedBy: input.uploadedBy,
     })
     .returning();
-  if (!row) throw new Error('Failed to record brochure version');
+  if (!row)
+    throw new CodedError('INSERT_RETURNING_EMPTY', {
+      internalMessage: 'Failed to record brochure version',
+    });
   return row;
 }