chore: configure monorepo workspace

Add pnpm workspace configuration, Node version specification, root package.json with build/test/lint scripts, and shared TypeScript configuration

tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "extends": "./tsconfig.base.json",
+  "compilerOptions": {
+    "outDir": "./dist",
+    "baseUrl": "./"
+  },
+  "references": [
+    { "path": "./packages/core" },
+    { "path": "./packages/server" },
+    { "path": "./packages/cli" },
+    { "path": "./packages/sdk" },
+    { "path": "./packages/mcp" },
+    { "path": "./packages/vscode" }
+  ],
+  "files": []
+}