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

tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "target": "ES2022",
+    "outDir": "out",
+    "lib": ["ES2022"],
+    "sourceMap": true,
+    "rootDir": "src",
+    "strict": true
+  },
+  "exclude": ["node_modules", ".vscode-test"]
+}