bug: refactor npm tarballs include compiled native binaries

## Description

On the `refactor` branch, the npm package's `files` allowlist includes all of `dist`. Packing a workspace after compiling native binaries therefore includes `dist/bin` and any other stale build output in the npm tarball.

## Reproduction

```sh
bun install --frozen-lockfile
bun run build
bun run compile:linux-x64
bun pm pack --ignore-scripts
tar -tzf aws-agentcore-*.tgz
```

No publishing is needed to reproduce this.

## Actual Behavior

The tarball includes `dist/bin/agentcore-linux-x64`. In a local reproduction, adding just this binary increased the compressed package from 1.44 MB to 40.37 MB. Other files left under `dist`, such as source maps, logs, and old build directories, are also included.

The automated release currently packs before compilation, which avoids the binaries on a fresh runner, but the package metadata does not enforce that separation for manual packaging or a reused build directory.

## Expected Behavior

Publish only the Node launcher, Node bundle, runtime assets, and standard package metadata to npm. Keep standalone native binaries as separate GitHub release assets, regardless of build/pack order.

## Environment

- Branch: `refactor`
- Base commit: `4fe2c108`
- Bun: 1.4.0
- Platform: Linux x64

Start with the npm package metadata that defines the `files` allowlist, then reproduce the issue with `bun pm pack --ignore-scripts` after the listed build and native compilation commands. Done means the tarball contains the Node launcher, bundle, runtime assets, and standard metadata, while excluding `dist/bin` and stale build output.

Written by the indexing model from the issue text.