feat(multienv): Add multi-env templates enabling TypeScript decorators for Bun and Deno; rename npmextra config key to szci

assets/templates/multienv/deno.json

@@ -0,0 +1,8 @@
+{
+  "compilerOptions": {
+    "experimentalDecorators": true,
+    "lib": ["ES2022", "DOM"],
+    "target": "ES2022"
+  },
+  "nodeModulesDir": true
+}