Update Node.js and VS Code dependencies to latest compatible versions (…

…#392)

- Bumped Node.js version in `.nvmrc` to `v20.17.0` to align with updated project requirements.
- Updated `@types/vscode` dependency to `1.85.0` in `package.json` and `package-lock.json`.
- Added `engines` field to `package.json` to enforce compatibility:
  - Node.js: `>=20.17.0`
  - VS Code: `^1.85.0`

.nvmrc

@@ -1 +1 @@
-v18.11.0
+v20.17.0

package.json

@@ -17,6 +17,10 @@
   "main": "./build/cjs/index.js",
   "module": "./build/esm/index.js",
   "browser": "./build/browser/index.js",
+  "engines": {
+    "vscode": "^1.85.0",
+    "node": ">=20.17.0"
+  },
   "exports": {
     "./webview": "./build/webview.js",
     ".": {
@@ -66,7 +70,7 @@
     "vitest": "^2.1.5"
   },
   "dependencies": {
-    "@types/vscode": "1.78.0",
+    "@types/vscode": "1.85.0",
     "@types/vscode-webview": "^1.57.5",
     "@vscode/extension-telemetry": "^0.9.7",
     "tangle": "^4.0.0"