Fix: one failing exporter should not abort the others (#754)

## Problem

When one exporter's `exportTransactions` throws, the entire export
pipeline aborts:

1. Per-exporter catch block re-throws the error
2. `Promise.all(exportPromises)` rejects fail-fast
3. Other still-running exporters are orphaned
4. `log.summary()` never runs
5. `EXPORT_PROCESS_END` event never fires
6. `yarn scrape` exits non-zero

A single exporter hitting a runtime error prevents all other exporters
from completing, even though their work is independent.

## Fix

1. **Remove the `throw e`** in the per-exporter catch block. The outcome
is already recorded via `successCount`/`failedCount` counters and the
`EXPORTER_ERROR` event — re-throwing adds nothing but the fail-fast
behavior.
2. **Switch `Promise.all` → `Promise.allSettled`** so an error outside
the try/catch still cannot abort other exporters or skip the summary.

Added unit tests covering both invariants:
- one exporter throwing does not prevent the others from running
- the function resolves (does not reject) with a partial result

## Verification

- `yarn test:main` → 45 passed
- `yarn typecheck:main` → clean
- `yarn lint` → clean

Author: brafdlog

packages/main/src/backend/export/exportTransactions.test.ts

@@ -0,0 +1,84 @@
+import { type EventPublisher } from '@/backend/eventEmitters/EventEmitter';
+import { beforeEach, describe, expect, test, vi } from 'vitest';
+
+// Mock the outputVendors module so we can inject controlled exporters.
+vi.mock('@/backend/export/outputVendors', () => ({
+  default: [],
+}));
+
+import outputVendors from '@/backend/export/outputVendors';
+import { createTransactionsInExternalVendors } from './exportTransactions';
+
+const noopEventPublisher: EventPublisher = {
+  emit: vi.fn().mockResolvedValue(undefined),
+};
+
+function makeExporter(name: string, behavior: 'success' | 'fail', exported = 1) {
+  return {
+    name,
+    init: vi.fn().mockResolvedValue(undefined),
+    exportTransactions: vi.fn().mockImplementation(async () => {
+      if (behavior === 'fail') {
+        throw new Error(`${name} blew up`);
+      }
+      return { exportedTransactionsNum: exported };
+    }),
+  };
+}
+
+function setExporters(list: unknown[]) {
+  // Mutate the mocked array in place so the module-level import in
+  // exportTransactions.ts sees the new values.
+  (outputVendors as unknown as unknown[]).length = 0;
+  (outputVendors as unknown as unknown[]).push(...list);
+}
+
+describe('createTransactionsInExternalVendors', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('one exporter failing does not prevent other exporters from running', async () => {
+    const failing = makeExporter('csv', 'fail');
+    const succeeding = makeExporter('ynab', 'success', 5);
+    setExporters([failing, succeeding]);
+
+    const config = {
+      csv: { active: true },
+      ynab: { active: true },
+    } as never;
+
+    const result = await createTransactionsInExternalVendors(
+      config,
+      { companyA: [] as never[] },
+      new Date('2025-01-01'),
+      noopEventPublisher,
+    );
+
+    // The successful exporter should have run to completion even though csv threw.
+    expect(succeeding.exportTransactions).toHaveBeenCalledTimes(1);
+    expect(failing.exportTransactions).toHaveBeenCalledTimes(1);
+    expect(result).toHaveProperty('ynab');
+    expect(result).not.toHaveProperty('csv');
+  });
+
+  test('does not reject when an exporter throws (promise resolves with partial result)', async () => {
+    const failing = makeExporter('csv', 'fail');
+    const succeeding = makeExporter('ynab', 'success', 3);
+    setExporters([failing, succeeding]);
+
+    const config = {
+      csv: { active: true },
+      ynab: { active: true },
+    } as never;
+
+    await expect(
+      createTransactionsInExternalVendors(
+        config,
+        { companyA: [] as never[] },
+        new Date('2025-01-01'),
+        noopEventPublisher,
+      ),
+    ).resolves.toBeDefined();
+  });
+});

packages/main/src/backend/export/exportTransactions.ts

@@ -106,11 +106,10 @@ export async function createTransactionsInExternalVendors(
           ...baseEvent,
         }),
       );
-      throw e;
     }
   });
 
-  await Promise.all(exportPromises);
+  await Promise.allSettled(exportPromises);
 
   const result = failedCount === 0 ? 'success' : successCount === 0 ? 'failed' : 'partial';
   log.summary(result, {