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/native/mod.rs

@@ -0,0 +1,39 @@
+//! Native desktop feature modules (Lotus Chat).
+//!
+//! Each feature lives in its own submodule exposing `#[tauri::command]`(s) and,
+//! when it needs to register listeners/state, a `setup(&AppHandle)`. lib.rs adds
+//! the commands to `generate_handler!` and calls `native::setup()` once during
+//! app setup. Windows-only pieces are guarded with `#[cfg(target_os = "windows")]`
+//! and compile-verified in CI (Gitea `windows` runner / GitHub `windows-latest`).
+
+use tauri::{AppHandle, Manager};
+
+pub mod chrome;
+pub mod jumplist;
+pub mod network;
+pub mod power;
+pub mod smtc;
+pub mod thumbbar;
+
+/// Dispatch a DOM `CustomEvent` to the web client (mirrors `forward_deeplink` in
+/// lib.rs) so native modules can push data to the frontend without pulling in
+/// `@tauri-apps/api` on the web side. `detail_json` MUST be valid JSON (use
+/// `serde_json::to_string`). `event` is a static, trusted name.
+#[allow(dead_code)]
+pub fn emit_to_web(app: &AppHandle, event: &str, detail_json: &str) {
+    if let Some(window) = app.get_webview_window("main") {
+        let _ = window.eval(&format!(
+            "window.dispatchEvent(new CustomEvent('{event}',{{detail:{detail_json}}}))"
+        ));
+    }
+}
+
+/// Called once from lib.rs `.setup()`. Feature modules that need to register OS
+/// listeners or managed state get initialized here. (power/jumplist/chrome are
+/// command-only and need no setup.)
+pub fn setup(app: &AppHandle) -> tauri::Result<()> {
+    thumbbar::setup(app)?;
+    smtc::setup(app)?;
+    network::setup(app)?;
+    Ok(())
+}