Add bootstrap entry for env-based proxy support

Introduces bootstrap.js to set NODE_USE_ENV_PROXY before loading main.js, ensuring proxy support is enabled unless explicitly opted out. Updates action.yml to use bootstrap as the main entry and modifies build script to bundle bootstrap.js.

action.yml

@@ -133,5 +133,5 @@ outputs:
     description: "GitHub App slug"
 runs:
   using: "node24"
-  main: "dist/main.cjs"
+  main: "dist/bootstrap.cjs"
   post: "dist/post.cjs"

bootstrap.js

@@ -0,0 +1,7 @@
+// Enable env-based proxy support (honors explicit opt-out if caller set NODE_USE_ENV_PROXY)
+if (process.env.NODE_USE_ENV_PROXY == null) {
+  process.env.NODE_USE_ENV_PROXY = "1";
+}
+
+// Defer to original main entry (dynamic import ensures above code runs first)
+await import("./main.js");

main.js

@@ -1,6 +1,4 @@
 // @ts-check
-process.env.NODE_USE_ENV_PROXY = "1";
-
 import core from "@actions/core";
 import { createAppAuth } from "@octokit/auth-app";
 

package.json

@@ -8,7 +8,7 @@
     "node": ">=24.4.0"
   },
   "scripts": {
-    "build": "esbuild main.js post.js --bundle --outdir=dist --out-extension:.js=.cjs --platform=node --packages=bundle",
+  "build": "esbuild bootstrap.js main.js post.js --bundle --outdir=dist --out-extension:.js=.cjs --platform=node --packages=bundle",
     "test": "c8 --100 ava tests/index.js",
     "coverage": "c8 report --reporter html",
     "postcoverage": "open-cli coverage/index.html"