feat(native): Tier A desktop features (P5-46/36/44/43/49) + window chrome (P5-47)

Adds a `native/` module system (each feature = its own module exposing
`#[tauri::command]`s + optional `setup`; `emit_to_web` pushes DOM CustomEvents to
the web like `forward_deeplink`). Wired into generate_handler! + native::setup;
windows-crate feature union added to Cargo.toml.

- power.rs (P5-46): SetThreadExecutionState held on the main thread while a call
  is active; released on end. Cross-platform (no-op off Windows).
- jumplist.rs (P5-36): ICustomDestinationList "Recent Rooms" of IShellLink tasks
  launching the exe with a matrix: arg (existing deep-link handler opens the room).
- thumbbar.rs (P5-44): ITaskbarList3 ThumbBar Mute/Deafen/End (GDI HICONs) + a
  window subclass catching THBN_CLICKED → emit thumbbar-action.
- smtc.rs (P5-43): WinRT SystemMediaTransportControls via GetForWindow; ButtonPressed
  → smtc-action; call-state command. (Experimental for a non-media app.)
- network.rs (P5-49): INetworkListManager poll thread → emit network-changed.
- chrome.rs (P5-47): cross-platform window-control commands + set_custom_chrome
  (set_decorations) for the opt-in TDS titlebar.

NOT compile-verified locally (no Rust/Windows toolchain on the dev box) — this is
for the CI Windows compile pass (GitHub test.yml / Gitea windows runner). Expect a
possible fixup round (windows-crate feature/namespace paths, e.g. subclass APIs).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -11,6 +11,8 @@ use tauri::{
 };
 use tauri_plugin_opener::OpenerExt;
 
+mod native;
+
 /// Bring the main window to the foreground from the tray / a hidden /
 /// minimized state. Shared by the tray, single-instance, and deep-link paths.
 fn show_main(app: &tauri::AppHandle) {
@@ -386,6 +388,15 @@ pub fn run() {
             send_notification,
             check_for_update,
             install_update,
+            native::power::set_call_active,
+            native::jumplist::set_jump_list,
+            native::thumbbar::set_thumbbar,
+            native::smtc::set_smtc_call_state,
+            native::chrome::set_custom_chrome,
+            native::chrome::window_minimize,
+            native::chrome::window_toggle_maximize,
+            native::chrome::window_start_drag,
+            native::chrome::window_close,
         ])
         .plugin(tauri_plugin_localhost::Builder::new(port).build())
         .plugin(tauri_plugin_window_state::Builder::default().build())
@@ -565,6 +576,9 @@ pub fn run() {
                 }
             })?;
 
+            // Native desktop feature modules (power/call-continuity, etc.).
+            native::setup(app.handle())?;
+
             Ok(())
         })
         .run(context)