The build config only had a Windows target. Adds a linux block producing
an AppImage, plus a 512x512 build/icon.png so the packaged app does not
ship with the stock Electron icon.
Verified by running the packaged binary: the embedded server comes up on
9095 and serves the overlay from process.resourcesPath, confirming the
extraResources mapping works in a packaged build.
StartupWMClass is deliberately not set via linux.desktop -- electron-builder
already emits the correct value, and the nested { entry: {...} } form leaks a
literal "entry=[object Object]" line into the .desktop file.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Removes extension/, desktop-client/backends/, desktop-client/config.js,
server/, root package.json/package-lock.json/node_modules/, and the
now-unused electron-store dependency from desktop-client/package.json.
The desktop-client is now a self-contained Electron app with no external
deps beyond express and ws.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>