fix: package zod with desktop sidecar - #165

Summary

• materialize the external zod runtime package under dist-electron/node_modules instead of relying on pnpm's symlink
• copy that directory beside the unpacked Desktop Host through Electron Builder extraResources
• extend package metadata and smoke coverage to require a real, non-symlinked Zod directory

Problem

The v0.6.3 Linux package starts Electron, but its Local Host exits before becoming healthy:

Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'zod' imported from .../app.asar.unpacked/dist-electron/backend.js
Backend sidecar exited { code: 1, signal: null }

zod is deliberately external because bundling its cyclic v4 modules breaks schema construction. The existing node_modules/zod/**/* file rule does not follow pnpm's symlink into the packaged application, so no resolvable Zod package reaches the release artifact. Electron Builder also filters nested node_modules from ordinary files, so the materialized package is delivered explicitly with extraResources.

Verification

• pnpm run check
• pnpm vp test scripts/electron-package-metadata.test.ts
• pnpm run build
• pnpm run test:package-smoke
• pnpm exec electron-builder --linux deb --publish never
• extracted the resulting .deb, verified resources/app.asar.unpacked/dist-electron/node_modules/zod/package.json, and started its backend.js; it remained healthy through the 8-second smoke timeout
• full local suite: 1,141 tests passed; three load-sensitive tests timed out/failed their timing bound when 217 workers ran concurrently, then all 13 tests passed with --maxWorkers=1; the browser audit could not launch Chromium because this Ubuntu host disables its usable sandbox