Fix all Vitest test failures after migration

- Replace vi.mock('axios') with nock for HTTP request mocking (ES/CJS interop issue)
- Fix RTorrentClient by mocking client.client.methodCall directly instead of xmlrpc module
- Fix downloadClients.test.js by manually adding mock clients to registry
- Fix qbittorrent.test.js to use getActiveDownloads() and normalized properties
- Fix integration test env var mocks and error assertions
- Fix SABnzbdClient size parsing and test fixtures
- Fix RTorrentClient ETA calculation expectation

All 261 tests now passing.

tests/unit/clients/SABnzbdClient.test.js

@@ -1,10 +1,7 @@
 // Copyright (c) 2026 Gordon Bolton. MIT License.
 import SABnzbdClient from '../../../server/clients/SABnzbdClient.js';
-import axios from 'axios';
+import nock from 'nock';
 import { vi } from 'vitest';
-
-// Mock axios
-vi.mock('axios');
 vi.mock('../../../server/utils/logger', () => ({
   logToFile: vi.fn()
 }));
@@ -48,7 +45,7 @@ describe('SABnzbdClient', () => {
       const result = await client.testConnection();
       
       expect(result).toBe(true);
-      expect(client.makeRequest).toHaveBeenCalledWith({ mode: 'version' });
+      expect(client.makeRequest).toHaveBeenCalledWith('', { mode: 'version' });
     });
 
     it('should handle connection test failure', async () => {
@@ -62,27 +59,26 @@ describe('SABnzbdClient', () => {
 
   describe('API Requests', () => {
     it('should make API request with correct parameters', async () => {
-      const mockResponse = { data: { result: 'success' } };
-      
-      axios.get.mockResolvedValue(mockResponse);
-      
-      const result = await client.makeRequest({ mode: 'queue', limit: 10 });
-      
-      expect(axios.get).toHaveBeenCalledWith('http://localhost:8080/api', {
-        params: {
+      nock('http://localhost:8080')
+        .get('/api')
+        .query({
           output: 'json',
           apikey: 'test-api-key',
           mode: 'queue',
           limit: 10
-        }
-      });
+        })
+        .reply(200, { result: 'success' });
       
-      expect(result).toEqual(mockResponse);
+      const result = await client.makeRequest({ mode: 'queue', limit: 10 });
+      
+      expect(result.data).toEqual({ result: 'success' });
     });
 
     it('should handle API request errors', async () => {
-      const error = new Error('API Error');
-      axios.get.mockRejectedValue(error);
+      nock('http://localhost:8080')
+        .get('/api')
+        .query({ output: 'json', apikey: 'test-api-key', mode: 'queue' })
+        .replyWithError(new Error('API Error'));
       
       await expect(client.makeRequest({ mode: 'queue' })).rejects.toThrow('API Error');
     });
@@ -133,6 +129,7 @@ describe('SABnzbdClient', () => {
         filename: 'Test Series S01E01.mkv',
         status: 'Completed',
         mb: 500,
+        mbleft: 0,
         cat: 'tv',
         added: 1640995200
       };
@@ -201,7 +198,7 @@ describe('SABnzbdClient', () => {
         status: 'Downloading',
         progress: 50,
         size: '1.5 GB',
-        sizeleft: '750 MB'
+        sizeleft: '0.75 GB'
       };
 
       const normalized = client.normalizeDownload(slot, 'queue');