Initial version of .NET Solution Launcher

Startup project and solution configuration (Debug|x64, Test|x64, ...) in
the status bar, with build and debug tasks that pass both configuration
and platform. Made for DotRush, whose build never passes -p:Platform and
whose status item shows the configuration but not the project.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0169iPWwKHZoBTNN9qwXiwqk

src/test/runTest.ts

@@ -0,0 +1,37 @@
+import * as path from 'path';
+import * as fs from 'fs';
+import { runTests } from '@vscode/test-electron';
+
+/**
+ * Launches VS Code on a real solution folder and runs the integration suite.
+ *
+ * Other extensions are disabled: DotRush is not needed to select a project and build a
+ * launch configuration, and without it the run cannot be influenced by its own state.
+ */
+async function main(): Promise<void> {
+    const extensionDevelopmentPath = path.resolve(__dirname, '../../');
+    const extensionTestsPath = path.resolve(__dirname, './suite/index');
+
+    const folder = path.normalize(process.env.SOLUTION_TEST_FOLDER ?? 'D:/Projects/MyGame');
+    if (!fs.existsSync(folder)) {
+        throw new Error(`Test folder does not exist: ${folder}`);
+    }
+    console.log(`[runTest] folder: ${folder}`);
+
+    await runTests({
+        extensionDevelopmentPath,
+        extensionTestsPath,
+        launchArgs: [
+            folder,
+            '--disable-extensions',
+            '--disable-workspace-trust',
+            '--skip-welcome',
+            '--skip-release-notes',
+        ],
+    });
+}
+
+main().catch(err => {
+    console.error('Integration tests failed:', err);
+    process.exit(1);
+});