63b45e03ab82f045ffaf208b1c22b3304e9ac6b7
iced's `window::settings::PlatformSpecific::application_id` only exists on Linux (X11/Wayland use it to match the .desktop launcher icon); on Windows the struct exposes a different field set, so the unconditional assignment failed to compile for `*-pc-windows-*`. This was the first real Windows compile blocker surfaced now that the port actually cross-compiles. Move the field behind a `platform_specific_settings()` helper gated on `target_os = "linux"`, with a defaults-only variant elsewhere. Linux build unchanged (verified `cargo check`); the windows-gnu target now builds a runnable .exe (verified launching under Wine: GUI renders, iroh network stack + ring identity init, config/identity land in %APPDATA%). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>