fix(companion): resolve fixtures path correctly in Electron runtime

apps/companion/main/di-container.ts

@@ -1,3 +1,5 @@
+import { app } from 'electron';
+import * as path from 'path';
 import { InMemorySessionRepository } from '@/packages/infrastructure/repositories/InMemorySessionRepository';
 import { MockBrowserAutomationAdapter } from '@/packages/infrastructure/adapters/automation/MockBrowserAutomationAdapter';
 import { BrowserDevToolsAdapter } from '@/packages/infrastructure/adapters/automation/BrowserDevToolsAdapter';
@@ -165,6 +167,24 @@ export class DIContainer {
     return this.permissionService;
   }
 
+  /**
+   * Resolve the fixtures path relative to the monorepo root.
+   * In Electron, app.getAppPath() returns the path to the app's main directory
+   * (e.g., apps/companion/dist/main in development, or the asar in production).
+   * We navigate up to find the monorepo root and then join with the resources path.
+   */
+  private resolveFixturesPath(configuredPath: string): string {
+    if (path.isAbsolute(configuredPath)) {
+      return configuredPath;
+    }
+    
+    const appPath = app.getAppPath();
+    const projectRoot = path.resolve(appPath, '../../../');
+    const resolvedPath = path.join(projectRoot, configuredPath);
+    
+    return resolvedPath;
+  }
+
   /**
    * Initialize fixture server for development mode.
    * Starts an embedded HTTP server serving static HTML fixtures.
@@ -185,7 +205,13 @@ export class DIContainer {
 
     this.fixtureServer = new FixtureServerService();
     const port = config.fixtureServer.port;
-    const fixturesPath = config.fixtureServer.fixturesPath;
+    const fixturesPath = this.resolveFixturesPath(config.fixtureServer.fixturesPath);
+
+    this.logger.debug('Fixture server path resolution', {
+      configuredPath: config.fixtureServer.fixturesPath,
+      appPath: app.getAppPath(),
+      resolvedPath: fixturesPath
+    });
 
     try {
       await this.fixtureServer.start(port, fixturesPath);