Allow desktop app to connect to selfhosted servers (#4902)

# Description of Changes
Changes the desktop app to allow connections to self-hosted servers on
first startup. This was quite involved and hit loads of CORS issues all
through the stack, but I think it's working now. This also changes the
bundled backend to spawn on an OS-decided port rather than always
spawning on `8080`, which means that the user can have other things
running on port `8080` now and the app will still work fine. There were
quite a few places that needed to be updated to decouple the app from
explicitly using `8080` and I was originally going to split those
changes out into another PR (#4939), but I couldn't get it working
independently in the time I had, so the diff here is just going to be
complex and contian two distinct changes - sorry 🙁

frontend/vitest.config.ts

@@ -2,52 +2,87 @@ import { defineConfig } from 'vitest/config';
 import react from '@vitejs/plugin-react-swc';
 import tsconfigPaths from 'vite-tsconfig-paths';
 
-export default defineConfig((configEnv) => {
-  const isProprietary = process.env.DISABLE_ADDITIONAL_FEATURES !== 'true';
-  const isDesktopMode =
-    configEnv.mode === 'desktop' ||
-    process.env.STIRLING_DESKTOP === 'true' ||
-    process.env.VITE_DESKTOP === 'true';
-
-  const baseProject = isProprietary ? './tsconfig.proprietary.json' : './tsconfig.core.json';
-  const desktopProject = isProprietary ? './tsconfig.desktop.json' : baseProject;
-  const tsconfigProject = isDesktopMode ? desktopProject : baseProject;
-
-  return {
-    plugins: [
-      react(),
-      tsconfigPaths({
-        projects: [tsconfigProject],
-      }),
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'jsdom',
+    setupFiles: ['./src/core/setupTests.ts'],
+    css: false,
+    exclude: [
+      'node_modules/',
+      'src/**/*.spec.ts', // Exclude Playwright E2E tests
+      'src/tests/test-fixtures/**'
     ],
-    test: {
-      globals: true,
-      environment: 'jsdom',
-      setupFiles: ['./src/core/setupTests.ts'],
-      css: false, // Disable CSS processing to speed up tests
-      include: [
-        'src/**/*.{test,spec}.{js,mjs,cjs,ts,mts,cts,jsx,tsx}'
-      ],
+    testTimeout: 10000,
+    hookTimeout: 10000,
+    coverage: {
+      reporter: ['text', 'json', 'html'],
       exclude: [
         'node_modules/',
-        'src/**/*.spec.ts', // Exclude Playwright E2E tests
-        'src/tests/test-fixtures/**'
-      ],
-      testTimeout: 10000, // 10 second timeout
-      hookTimeout: 10000, // 10 second timeout for setup/teardown
-      coverage: {
-        reporter: ['text', 'json', 'html'],
-        exclude: [
-          'node_modules/',
-          'src/core/setupTests.ts',
-          '**/*.d.ts',
-          'src/tests/test-fixtures/**',
-          'src/**/*.spec.ts' // Exclude Playwright files from coverage
-        ]
-      }
+        'src/core/setupTests.ts',
+        '**/*.d.ts',
+        'src/tests/test-fixtures/**',
+        'src/**/*.spec.ts'
+      ]
     },
-    esbuild: {
-      target: 'es2020' // Use older target to avoid warnings
-    }
-  };
+    projects: [
+      {
+        test: {
+          name: 'core',
+          include: ['src/core/**/*.test.{ts,tsx}'],
+          environment: 'jsdom',
+          globals: true,
+          setupFiles: ['./src/core/setupTests.ts'],
+        },
+        plugins: [
+          react(),
+          tsconfigPaths({
+            projects: ['./tsconfig.core.json'],
+          }),
+        ],
+        esbuild: {
+          target: 'es2020'
+        }
+      },
+      {
+        test: {
+          name: 'proprietary',
+          include: ['src/proprietary/**/*.test.{ts,tsx}'],
+          environment: 'jsdom',
+          globals: true,
+          setupFiles: ['./src/core/setupTests.ts'],
+        },
+        plugins: [
+          react(),
+          tsconfigPaths({
+            projects: ['./tsconfig.proprietary.json'],
+          }),
+        ],
+        esbuild: {
+          target: 'es2020'
+        }
+      },
+      {
+        test: {
+          name: 'desktop',
+          include: ['src/desktop/**/*.test.{ts,tsx}'],
+          environment: 'jsdom',
+          globals: true,
+          setupFiles: ['./src/core/setupTests.ts'],
+        },
+        plugins: [
+          react(),
+          tsconfigPaths({
+            projects: ['./tsconfig.desktop.json'],
+          }),
+        ],
+        esbuild: {
+          target: 'es2020'
+        }
+      },
+    ],
+  },
+  esbuild: {
+    target: 'es2020'
+  }
 });