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/components/shared/addresses-editor.tsx

@@ -11,6 +11,7 @@ import { CountryCombobox } from '@/components/shared/country-combobox';
 import { SubdivisionCombobox } from '@/components/shared/subdivision-combobox';
 import { InlineEditableField } from '@/components/shared/inline-editable-field';
 import { apiFetch } from '@/lib/api/client';
+import { toastError } from '@/lib/api/toast-error';
 import type { CountryCode } from '@/lib/i18n/countries';
 import { getCountryName } from '@/lib/i18n/countries';
 import { getSubdivisionName } from '@/lib/i18n/subdivisions';
@@ -119,7 +120,7 @@ function AddressCard({
     try {
       await onUpdate({ isPrimary: true });
     } catch (err) {
-      toast.error(err instanceof Error ? err.message : 'Failed to update');
+      toastError(err);
     }
   }
 
@@ -362,7 +363,7 @@ function NewAddressForm({
         isPrimary: makePrimary,
       });
     } catch (err) {
-      toast.error(err instanceof Error ? err.message : 'Failed to add address');
+      toastError(err);
     } finally {
       setSaving(false);
     }

src/components/shared/inline-country-field.tsx

@@ -2,9 +2,9 @@
 
 import { useRef, useState } from 'react';
 import { Loader2, Pencil } from 'lucide-react';
-import { toast } from 'sonner';
 
 import { CountryCombobox } from '@/components/shared/country-combobox';
+import { toastError } from '@/lib/api/toast-error';
 import { getCountryName, type CountryCode } from '@/lib/i18n/countries';
 import { cn } from '@/lib/utils';
 
@@ -46,7 +46,7 @@ export function InlineCountryField({
       await onSave(next);
       setEditing(false);
     } catch (err) {
-      toast.error(err instanceof Error ? err.message : 'Failed to save');
+      toastError(err);
     } finally {
       setSaving(false);
     }

src/components/shared/inline-editable-field.tsx

@@ -2,8 +2,8 @@
 
 import { useEffect, useRef, useState } from 'react';
 import { Loader2, Pencil } from 'lucide-react';
-import { toast } from 'sonner';
 
+import { toastError } from '@/lib/api/toast-error';
 import { Input } from '@/components/ui/input';
 import { Textarea } from '@/components/ui/textarea';
 import {
@@ -85,7 +85,7 @@ export function InlineEditableField(props: InlineEditableFieldProps) {
       await onSave(trimmed === '' ? null : trimmed);
       setEditing(false);
     } catch (err) {
-      toast.error(err instanceof Error ? err.message : 'Failed to save');
+      toastError(err);
       setDraft(value ?? '');
     } finally {
       setSaving(false);

src/components/shared/inline-phone-field.tsx

@@ -2,9 +2,9 @@
 
 import { useState } from 'react';
 import { Loader2, Pencil } from 'lucide-react';
-import { toast } from 'sonner';
 
 import { PhoneInput, type PhoneInputValue } from '@/components/shared/phone-input';
+import { toastError } from '@/lib/api/toast-error';
 import { parsePhone } from '@/lib/i18n/phone';
 import type { CountryCode } from '@/lib/i18n/countries';
 import { cn } from '@/lib/utils';
@@ -66,7 +66,7 @@ export function InlinePhoneField({
       await onSave(next);
       setEditing(false);
     } catch (err) {
-      toast.error(err instanceof Error ? err.message : 'Failed to save');
+      toastError(err);
     } finally {
       setSaving(false);
     }

src/components/shared/inline-tag-editor.tsx

@@ -3,11 +3,11 @@
 import { useState } from 'react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { Plus, X, Check } from 'lucide-react';
-import { toast } from 'sonner';
 
 import { Button } from '@/components/ui/button';
 import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover';
 import { apiFetch } from '@/lib/api/client';
+import { toastError } from '@/lib/api/toast-error';
 import { cn } from '@/lib/utils';
 
 interface Tag {
@@ -45,7 +45,7 @@ export function InlineTagEditor({
   const setTags = useMutation({
     mutationFn: (tagIds: string[]) => apiFetch(endpoint, { method: 'PUT', body: { tagIds } }),
     onSuccess: () => qc.invalidateQueries({ queryKey: invalidateKey }),
-    onError: (err) => toast.error(err instanceof Error ? err.message : 'Failed to update tags'),
+    onError: (err) => toastError(err),
   });
 
   function toggleTag(tagId: string) {

src/components/shared/inline-timezone-field.tsx

@@ -2,9 +2,9 @@
 
 import { useRef, useState } from 'react';
 import { Loader2, Pencil } from 'lucide-react';
-import { toast } from 'sonner';
 
 import { TimezoneCombobox } from '@/components/shared/timezone-combobox';
+import { toastError } from '@/lib/api/toast-error';
 import { formatTimezoneLabel } from '@/lib/i18n/timezones';
 import type { CountryCode } from '@/lib/i18n/countries';
 import { cn } from '@/lib/utils';
@@ -46,7 +46,7 @@ export function InlineTimezoneField({
       await onSave(next);
       setEditing(false);
     } catch (err) {
-      toast.error(err instanceof Error ? err.message : 'Failed to save');
+      toastError(err);
     } finally {
       setSaving(false);
     }

src/components/shared/send-document-dialog.tsx

@@ -33,6 +33,7 @@ import { Label } from '@/components/ui/label';
 import { Textarea } from '@/components/ui/textarea';
 import { Input } from '@/components/ui/input';
 import { apiFetch } from '@/lib/api/client';
+import { toastError } from '@/lib/api/toast-error';
 
 const BODY_MAX = 50_000;
 
@@ -149,7 +150,7 @@ export function SendDocumentDialog({
       }
     },
     onError: (err) => {
-      toast.error(err instanceof Error ? err.message : 'Send failed');
+      toastError(err);
     },
   });