refactor(runtime): compose consumers over fs and subprocess

packages/subprocess/subprocess-local/package.json

@@ -21,8 +21,12 @@
   "files": [
     "lib/index.js",
     "lib/invariant.js",
+    "scripts/ensure-spawn-helper.mjs",
     "lib/types/**/*.d.ts"
   ],
+  "scripts": {
+    "postinstall": "node scripts/ensure-spawn-helper.mjs"
+  },
   "license": "BSD-3-Clause",
   "peerDependencies": {
     "@deepseek-ai/dsh-invariants": "^0.0.1",
@@ -30,6 +34,9 @@
     "@deepseek-ai/dsh-timeout": "^0.0.1",
     "cordis": "^4.0.0-rc.7"
   },
+  "dependencies": {
+    "node-pty": "^1.1.0"
+  },
   "devDependencies": {
     "@deepseek-ai/dsh-invariants": "workspace:^",
     "@deepseek-ai/dsh-subprocess": "workspace:^",