fix: stabilize cross-platform CI checks

Use the repository's default Electron import pattern in the MCP OAuth service, make the attachment-path test platform-neutral, and ensure the hook runner cwd/env test drains stdin before asserting shell output.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

sidecar/tests/Aryx.AgentHost.Tests/AryxCopilotAgentMessageOptionsTests.cs

@@ -10,13 +10,14 @@ public sealed class AryxCopilotAgentMessageOptionsTests
     [Fact]
     public async Task ProcessMessageAttachmentsAsync_MapsProtocolAttachmentsAndMessageMode()
     {
+        string attachmentPath = Path.GetFullPath(Path.Combine(Path.GetTempPath(), "aryx-tests", "assets", "diagram.png"));
         ChatMessage message = new(ChatRole.User, "Please inspect these images.");
         message.Contents.Add(new AIContent
         {
             RawRepresentation = new ChatMessageAttachmentDto
             {
                 Type = "file",
-                Path = @"C:\workspace\project\assets\diagram.png",
+                Path = attachmentPath,
                 DisplayName = "diagram.png",
             },
         });
@@ -47,7 +48,7 @@ public sealed class AryxCopilotAgentMessageOptionsTests
             first =>
             {
                 UserMessageDataAttachmentsItemFile file = Assert.IsType<UserMessageDataAttachmentsItemFile>(first);
-                Assert.Equal(@"C:\workspace\project\assets\diagram.png", file.Path);
+                Assert.Equal(attachmentPath, file.Path);
                 Assert.Equal("diagram.png", file.DisplayName);
             },
             second =>

sidecar/tests/Aryx.AgentHost.Tests/HookCommandRunnerTests.cs

@@ -71,8 +71,8 @@ public sealed class HookCommandRunnerTests
         string hooksDirectory = Directory.CreateDirectory(Path.Combine(project.Path, "scripts")).FullName;
         HookCommandDefinition hook = CreatePlatformHook(
             OperatingSystem.IsWindows()
-                ? "Write-Output ((Get-Location).Path + '|' + $env:HOOK_TEST_ENV)"
-                : "printf '%s|%s' \"$(pwd)\" \"$HOOK_TEST_ENV\"",
+                ? "$null = [Console]::In.ReadToEnd(); Write-Output ([Environment]::CurrentDirectory + '|' + $env:HOOK_TEST_ENV)"
+                : "cat >/dev/null; printf '%s|%s' \"$(pwd)\" \"$HOOK_TEST_ENV\"",
             cwd: "scripts",
             env: new Dictionary<string, string>
             {

src/main/services/mcpOAuthService.ts

@@ -1,12 +1,14 @@
 import { randomBytes, createHash } from 'node:crypto';
 import { createServer, type Server, type IncomingMessage, type ServerResponse } from 'node:http';
 
-import { shell } from 'electron';
+import electron from 'electron';
 
 import type { McpOauthStaticClientConfig } from '@shared/domain/mcpAuth';
 
 import { storeToken, buildWellKnownUrl, buildWellKnownUrlFallback, type McpOAuthToken } from './mcpTokenStore';
 
+const { shell } = electron;
+
 /* ── Public API ──────────────────────────────────────────────── */
 
 export interface McpOAuthFlowOptions {