[WillTDA]

• electron-builder.cjs, from the kit's config(). package.json's build moves there, with the 22 types as fileTypes and "Convert with Diamond File Converter" on files and folders as contextMenu. installer.nsh goes.
  • Windows: the installer asks who it's for ("Only for me" by default, no administrator prompt). An install for everyone, as every earlier version's was, is upgraded in place, never joined by a second. It then asks which types to open and whether to add the right-click entry. It writes the same DiamondFileConverter key installer.nsh did, and the old version's uninstaller removes its own file associations during the update, so nothing shows twice.
  • Linux: the .deb and .rpm put the app in Open With for each type, and the dock shows its icon.
• start({ appId }): Windows groups the window under its pinned icon and shows its notifications.
• mountShell({ busy }): Restart Now asks first while a conversion or a join runs.
• electron-kit 0.1.0-beta.8 (from beta.3): Settings > Update's Restart Now, the download's bar, no install ID on disk, and a status line that's never empty before the first check (opening the tab runs the launch check).
• The README's installation, the design-system note, and a 2.0.0-beta.6 section in MANUAL-TESTING.md.

198 tests pass. A trial Windows build made the asking installer (oneClick=false, perMachine=false).