Build Windows and macOS installers

Build a Windows or macOS installer for my TabTin-based product. Success means an artifact that installs, starts, and shows the right brand—not merely a packaging command that exits zero.

Read AGENTS.md, the Electron package configuration in apps/tabtin-electron, and docs/agent/electron-production-release-sop.md. Confirm target OS and CPU, product name, version, app identifier, icons, update endpoint, and signing conditions. Never expose certificates, private keys, or passwords in code, command history, or the report. Label an unsigned build as local testing only.

Check that production main/preload/renderer builds and packaging agree. Review external assets, native dependencies, protocol registration, data directories, auto-update, and uninstall policy. Run the target build; separate what can be packaged cross-platform from signing steps that require the target OS. Fix missing assets, architecture mismatch, native rebuilds, and case-sensitive paths without overwriting an official artifact. Output a clear artifact path and checksum.

Install and launch on the target OS or a trusted matching environment. Verify name, icon, window, sign-in, protocol links, update, and uninstall. Check macOS signing/notarization or Windows signing/install location, and prove uninstall does not delete a user Workspace or bound directory.

Report environment, version, artifact and hash, signing state, installation evidence, remaining store/notarization work, and whether the package is customer-ready. Do not publish a Release, upload the installer, or commit without permission.