Epic: Ship the cross-platform ProPR desktop application

[propr-dev]

Goal

Build and release an end-to-end Electron desktop application for Linux, macOS, and Windows. It presents ProPR as a native desktop-shaped experience, connects to local or remote ProPR instances through supported APIs, and provides guided local setup where the runtime is supported.

Integration tree

• Sub-epic: Desktop transport, compatibility, and authentication #1953 — transport, compatibility, and authentication (1953-epic-desktop-transport-api)
• Sub-epic: Electron runtime, packaging, and release pipeline #1952 — Electron runtime, packaging, and releases (1952-epic-electron-runtime-app)
• Sub-epic: Desktop experience and guided local setup #1951 — desktop experience and local setup (1951-epic-desktop-experience-uxs)
• Complete desktop end-to-end UX, visual polish, and smoke coverage #1962 — final end-to-end UX and verification

Top-level branch: 1950-epic-cross-platform-dsk. The final epic PR targets main, remains unmerged, and must pass Ultrafix plus independent build and visual review.

Product requirements

• Desktop stays in this monorepo under apps/desktop and reuses propr-ui.
• Local and remote instances use shared HTTP and Socket.IO contracts.
• Remote connections work on Linux, macOS, and Windows.
• Local setup is guided on Linux; unsupported local macOS/Windows runtime behavior is represented honestly.
• Privileged host operations remain behind a narrow Electron main/preload API.
• Native CI produces installable artifacts and documents signing/notarization.
• Automated, package, security, and visual checks cover the completed flows.