Move proxy setup to request.js and update entrypoint

Proxy environment setup previously in bootstrap.js is now handled in lib/request.js for better encapsulation. The action entrypoint is updated from dist/bootstrap.cjs to dist/main.cjs, and bootstrap.js is removed. Build script is updated to exclude bootstrap.js.

lib/request.js

@@ -1,6 +1,28 @@
 import core from "@actions/core";
 import { request } from "@octokit/request";
 
+/* c8 ignore start -- proxy setup depends on external runner env */
+// Ensure env-based proxying for Node core agents unless explicitly disabled.
+if (process.env.NODE_USE_ENV_PROXY == null) {
+  process.env.NODE_USE_ENV_PROXY = "1";
+}
+// Attempt to configure undici global dispatcher (used by octokit under the hood)
+// if a proxy environment variable is present. Failures are non-fatal.
+const __proxyUrl =
+  process.env.HTTPS_PROXY || process.env.HTTP_PROXY || process.env.ALL_PROXY;
+if (__proxyUrl) {
+  (async () => {
+    try {
+      const { setGlobalDispatcher, ProxyAgent } = await import("undici");
+      setGlobalDispatcher(new ProxyAgent(__proxyUrl));
+    } catch (e) {
+      // eslint-disable-next-line no-console
+      console.warn("Proxy setup failed:", e.message);
+    }
+  })();
+}
+/* c8 ignore stop */
+
 // Get the GitHub API URL from the action input and remove any trailing slash
 const baseUrl = core.getInput("github-api-url").replace(/\/$/, "");