fix(i18n): translate Unknown Income/Expense and other missing ES strings (#331)

## Summary

Fixes untranslated strings surfaced in the Spanish UI (e.g. `Unknown
Income`, `Unknown Expense` on the cashflow breakdown).

## Root cause

`CashflowAnalyticsController` pushed literal English names into the API
response for uncategorized totals, bypassing `__()`. Additional `__()`
calls across the sync flow and validation had no matching keys in
`lang/es.json`. Several frontend toasts/errors were also hardcoded.

## Changes

**Controller (P0)**
- `app/Http/Controllers/Api/CashflowAnalyticsController.php` — wrap
`Unknown Income`/`Unknown Expense` with `__()` (lines 250, 323).

**Translations (P0 + P1 + P2)**
- `lang/es.json` — added 23 keys (1730 → 1753):
  - `Unknown Income`, `Unknown Expense`, `Unknown Bank`, `Unknown error`
- Sync/banking messages: `Invalid credentials…`, `Rate limit exceeded…`,
`Failed to sync with the provider…`, `The provider is experiencing
issues…`, `An unexpected error occurred during sync…`, `Credentials
updated. Sync started.`, `Action required: :provider connection needs
attention`, `:count new transactions synced on Whisper Money`
- Validation: `The selected property cannot be linked.`, `The selected
property is already linked to a loan.`, `The verification link is
invalid.`, `This field is required.`
- Misc: `Confirm your waitlist spot - Whisper Money`, `Log in to your
bank`
- Frontend toasts: `Failed to re-evaluate rules. Please try again.`,
`Failed to load import data`, `All transactions failed to import`,
`Failed to update transactions`, `Failed to update transactions with
labels`

**Frontend hardcoded strings wrapped in `__()` (P2)**
- `resources/js/components/transactions/import-transactions-drawer.tsx`
- `resources/js/components/accounts/import-balances-drawer.tsx`
- `resources/js/lib/sync-manager.ts` (added `@/utils/i18n` import)
- `resources/js/components/transactions/transaction-list.tsx`
- `resources/js/components/transactions/import-transactions-button.tsx`
- `resources/js/pages/transactions/index.tsx`

## Verification

- `vendor/bin/pint --dirty` → pass
- `php artisan test --filter=CashflowAnalytics` → 24 passed
- `php artisan test --filter=Sync` → 166 passed
- `npm run build` → OK
- Post-fix audit: 0 real missing `__()` keys remaining

app/Http/Controllers/Api/CashflowAnalyticsController.php

@@ -247,7 +247,7 @@ class CashflowAnalyticsController extends Controller
                 'category_id' => null,
                 'category' => (new Category)->forceFill([
                     'id' => null,
-                    'name' => $isIncome ? 'Unknown Income' : 'Unknown Expense',
+                    'name' => $isIncome ? __('Unknown Income') : __('Unknown Expense'),
                     'type' => $isIncome ? CategoryType::Income : CategoryType::Expense,
                     'color' => 'gray',
                     'icon' => 'HelpCircle',
@@ -320,7 +320,7 @@ class CashflowAnalyticsController extends Controller
                 'category_id' => null,
                 'category' => (new Category)->forceFill([
                     'id' => null,
-                    'name' => $type === CategoryType::Income ? 'Unknown Income' : 'Unknown Expense',
+                    'name' => $type === CategoryType::Income ? __('Unknown Income') : __('Unknown Expense'),
                     'type' => $type,
                     'color' => 'gray',
                     'icon' => 'HelpCircle',

resources/js/components/accounts/import-balances-drawer.tsx

@@ -487,7 +487,7 @@ export function ImportBalancesDrawer({
                     const errorMessage =
                         result.reason instanceof Error
                             ? result.reason.message
-                            : 'Unknown error';
+                            : __('Unknown error');
 
                     errors.push({
                         rowNumber,

resources/js/components/transactions/import-transactions-button.tsx

@@ -47,7 +47,7 @@ export function ImportTransactionsButton() {
             setImportData(data);
             setDrawerOpen(true);
         } catch (error) {
-            toast.error('Failed to load import data');
+            toast.error(__('Failed to load import data'));
             console.error(error);
         } finally {
             setLoading(false);

resources/js/components/transactions/import-transactions-drawer.tsx

@@ -430,7 +430,7 @@ export function ImportTransactionsDrawer({
                     const errorMessage =
                         result.reason instanceof Error
                             ? result.reason.message
-                            : 'Unknown error';
+                            : __('Unknown error');
 
                     console.error(`Transaction ${rowNumber} failed:`, {
                         transaction,
@@ -557,7 +557,7 @@ export function ImportTransactionsDrawer({
             });
             onOpenChange(false);
         } else {
-            toast.error('All transactions failed to import');
+            toast.error(__('All transactions failed to import'));
         }
 
         transactionSyncService

resources/js/components/transactions/transaction-list.tsx

@@ -932,7 +932,7 @@ export function TransactionList({
         } catch (error) {
             consoleDebug('❌ Error during bulk re-evaluation:', error);
             console.error('Failed to re-evaluate rules:', error);
-            toast.error('Failed to re-evaluate rules. Please try again.', {
+            toast.error(__('Failed to re-evaluate rules. Please try again.'), {
                 id: toastId,
             });
         } finally {

resources/js/lib/sync-manager.ts

@@ -1,3 +1,4 @@
+import { __ } from '@/utils/i18n';
 import type { Transaction } from '@/types/transaction';
 import type { UUID } from '@/types/uuid';
 import axios from 'axios';
@@ -64,7 +65,7 @@ export class TransactionSyncManager {
         } catch (error) {
             result.success = false;
             result.errors.push(
-                error instanceof Error ? error.message : 'Unknown error',
+                error instanceof Error ? error.message : __('Unknown error'),
             );
         } finally {
             this.syncInProgress = false;

resources/js/pages/transactions/index.tsx

@@ -719,7 +719,7 @@ export default function Transactions({
             refreshTransactions();
         } catch (error) {
             console.error('Failed to re-evaluate rules:', error);
-            toast.error('Failed to re-evaluate rules. Please try again.', {
+            toast.error(__('Failed to re-evaluate rules. Please try again.'), {
                 id: toastId,
             });
         } finally {
@@ -851,7 +851,7 @@ export default function Transactions({
             }
         } catch (error) {
             console.error('Failed to update transactions:', error);
-            toast.error('Failed to update transactions');
+            toast.error(__('Failed to update transactions'));
         } finally {
             setIsBulkUpdating(false);
         }
@@ -977,7 +977,7 @@ export default function Transactions({
             }
         } catch (error) {
             console.error('Failed to update transactions with labels:', error);
-            toast.error('Failed to update transactions with labels');
+            toast.error(__('Failed to update transactions with labels'));
         } finally {
             setIsBulkUpdating(false);
         }