fix push-to-action: use CLI direct invocation for token acquisition

the inline `node -e` + `TOKEN=$(...)` approach broke because
`core.getIDToken()` in @actions/core writes `::debug::` and
`::add-mask::` to stdout, polluting the captured value.

`node cli.ts gha token` uses `core.setOutput()` which writes to
the $GITHUB_OUTPUT file instead of stdout.

Made-with: Cursor

get-installation-token/post.ts

@@ -0,0 +1,6 @@
+import { runPullfrogCli } from "../runCli.ts";
+
+runPullfrogCli({
+  cliArgs: ["gha", "token", "--post"],
+  swallowErrors: true,
+});