fix: Windows Electron desktop build compatibility

[prasairaul-del]

Summary

Fixes Windows compatibility for the Electron desktop app (5 files changed, +361/-33).

Changes

electron/main.cjs — 6 Windows fixes

• fs import: full module import (not just { existsSync }) for fs.openSync/closeSync
• isHermesInstalled(): uses 'where hermes' on Windows, 'which hermes' on macOS/Linux
• getTempDir(): returns %TEMP% on Windows, /tmp on macOS/Linux
• spawnDetached(): uses cmd /c + windowsHide on Windows, bash -lc + nohup on macOS/Linux
• installHermesInBackground(): uses pip install on Windows (not curl|bash)
• desktop:open-logs: opens %TEMP% (not /tmp)

electron-builder.config.cjs

• Added executableName and artifactName for correct output files
• Added portable target alongside NSIS

package.json

• Removed NODE_OPTIONS prefix from build/dev/electron:dev scripts (breaks Windows cmd)

src/server/swarm-lifecycle.ts

• Added 'export' to sendToWorker function (fixes broken import in swarm-notifications.ts)

AGENTS.md

• Updated Windows setup notes with 3-service architecture and spawn fixes

Verified

• electron:dev boots successfully on Windows (enhanced status, all capabilities)
• electron:build:win produces working 204.7 MB installer
• App installs and runs from desktop shortcut
• PWA fallback at http://127.0.0.1:3000 remains functional