Embed mobile bridge adapter and add Platform backend abstraction

[dominicletz]

Summary

• Introduces a Desktop.Platform layer with domain behaviours (Window, Content, Notification, Media, System) routed to three backends: Desktop.Backend.Wx, Desktop.Backend.Json, and Desktop.Backend.Browser
• Embeds the mobile JSON/TCP bridge as Desktop.Bridge.Transport, removing the separate {:wx, hex: :bridge} dependency on Android/iOS
• Adds optional config :desktop, :backend, :auto | :wx | :json | :browser override, menu adapters for Json/Browser, compile-time wx stubs for builds without OTP :wx, and expanded test coverage (mix test.fast, mix test.wx, mix test.guard)

Test plan

• mix test.fast — fast tests without wx
• xvfb-run -a mix test.wx — wx backend tests
• mix test.guard — platform abstraction regression guards
• mix lint — compile, format, credo, dialyzer
• Verify mobile Json backend with BRIDGE_PORT against a native host
• Verify Browser backend with NO_WX=1 on headless Linux

Made with Cursor

[gemini-code-assist]

Code Review

This pull request refactors the library to introduce a unified Desktop.Platform abstraction layer with dedicated backends for Wx, JSON bridge, and Browser-based environments, enabling compilation and execution on mobile and headless targets without OTP :wx. The review feedback highlights several critical reliability and concurrency issues: synchronous TCP connections in init/1 and blocking reconnection loops in Desktop.Bridge.Transport can block the GenServer indefinitely; delegated callbacks in Desktop.Platform.Server do not properly wrap standard GenServer return tuples, risking state corruption; and using spawn_link/1 to run external commands in Desktop.Backend.Wx can crash the main GUI process upon failure.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.