Standalone clipboard native addon

Problem

The CLI bundle keeps @teddyzhu/clipboard external so npm installations can load the platform-specific native package at runtime. Standalone archives also keep the import external, but currently copy only the audio-capture native addon into lib/node_modules. Clipboard image paste therefore fails silently in every standalone archive.

Constraints

• Each archive must contain the @teddyzhu/clipboard JavaScript package and exactly one native package matching the archive target.
• The release job creates all supported targets on one Ubuntu runner. A normal npm ci only installs the runner's optional native package, so packaging cannot rely on the repository node_modules for cross-target artifacts.
• Clipboard package versions must come from the lockfile and remain aligned with the CLI optional dependencies.
• Local packaging should continue to work when a non-host clipboard artifact is unavailable, while release packaging must fail rather than publish a partially functional archive.

Design

Before building release archives, install the locked clipboard meta package and every supported target package into a temporary staging directory. Pass that directory explicitly to the per-target packaging command.

The standalone packager maps each target to its native clipboard package and copies only the meta package plus that target package into lib/node_modules/@teddyzhu. When no explicit staging directory is supplied, the packager uses the repository node_modules; a missing host artifact emits a warning for local builds. Missing artifacts in an explicit staging directory are fatal.

If the runtime module still cannot load, the input prompt reports a single user-visible error on the first clipboard-image paste attempt. Existing Linux wl-paste and xclip paths are unchanged.

Verification

• Packaging tests cover target selection, exclusion of other native targets, and failure for incomplete explicit staging.
• Clipboard and input prompt tests cover the unavailable-module callback and one-time UI error.
• A real macOS arm64 archive is unpacked outside the repository, loaded with its bundled Node.js runtime, and exercised against an actual PNG in the system clipboard.