fix(tauri): never spawn a console window on Windows

[statik]

Problem

When testing on Windows, running hyperdeck-adapter pops up a console window with text output. The app is tray-only — there should be no window.

Root cause

src-tauri/src/main.rs had the GUI-subsystem attribute gated on the build profile:

#[cfg_attr(not(debug_assertions), windows_subsystem = "windows")]

That only suppresses the console in release builds. But the ways the app is actually tested on Windows compile with debug_assertions on, so the guard is inactive and a console appears:

• just build → cargo tauri build --debug
• just run → cargo tauri dev

(There's no logger initialized, so the window is largely empty / shows only stray stderr — but it's still an unwanted window.)

Fix

Make the GUI subsystem unconditional so no build profile spawns a console:

#[windows_subsystem = "windows"]

To keep the --check-accessibility and --headless CLI modes usable from a terminal (they println!/eprintln!), the process now reattaches to the parent terminal's console via AttachConsole(ATTACH_PARENT_PROCESS) before those paths run. Launched from Explorer or a Start-menu shortcut there is no parent console, so it's a harmless no-op and still no window.

This adds a Windows-only windows crate dependency (Win32_System_Console); the same crate/version (0.58) is already in the tree via hyperdeck-os, so no new packages are pulled.

Testing notes

• Library workspace is unaffected (change is confined to src-tauri).
• cargo fmt --check passes in src-tauri.
• src-tauri requires the desktop webview toolchain and is built by the dedicated Windows/macOS CI jobs — needs a real Windows build to confirm end-to-end that the tray launch shows no console while --headless from a shell still prints.

🤖 Generated with Claude Code

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Generated by Claude Code