feat: add initial project configuration and smoke tests

- Created pnpm workspace configuration to manage packages.
- Added a placeholder .gitkeep file in the scripts directory.
- Implemented a smoke test script to validate core API and web endpoints.
- Established TypeScript base configuration for consistent compilation settings.
- Introduced Turbo configuration for task management and build processes.

.env.example

@@ -0,0 +1,15 @@
+# Database
+DATABASE_URL=postgresql://davinci:davinci@localhost:55434/davinci_platform_dev
+
+# Server
+PORT=3001
+NODE_ENV=development
+
+# Mode: "mothership" (default) or "community"
+DAVINCI_MODE=mothership
+
+# Auth (placeholder — configured in auth feature plan)
+JWT_SECRET=change-me-in-production
+
+# Frontend
+NEXT_PUBLIC_API_URL=http://localhost:3001/api