fix(native): toast coalescing, real reply target, Focus Assist mount query

- Rich toasts set a WinRT Tag (hash of the web notification tag, since
  room:thread tags exceed the 64-char limit) in a fixed Group, so a newer
  toast for the same room/thread replaces the older one instead of
  stacking; the replaced toast's keep-alive entry is dropped (#16).
- The bridge passes tag, roomId and threadId separately. The reply target
  is the real room id (+ thread), never the coalescing tag, which was
  `room:thread` for threads and `lotus-invites` for invites, so those
  replies failed silently. Toasts with no room id (invites) get no reply
  box (#17).
- New `get_focus_assist` command serves the latest Focus Assist poll so
  the web hook can hydrate on mount; the setup-time first emit was lost
  before the page listened (#15).
- Bump cinny to 3b6de2fd (the matching web-side hooks).

Closes #15, #16, #17

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src-tauri/src/lib.rs

@@ -70,14 +70,19 @@ const NOTIFICATION_BRIDGE: &str = r#"(function(){
     var opts=options||{};
     try{
       var body=opts.body!=null?String(opts.body):undefined;
-      // cinny tags message notifications with the roomId (options.tag) and the
-      // in-app route (options.data.path). When present, route to the rich WinRT
-      // toast (click-opens-room + quick reply); otherwise a plain toast.
-      var roomId=opts.tag!=null?String(opts.tag):undefined;
-      var path=(opts.data&&opts.data.path!=null)?String(opts.data.path):undefined;
-      if(roomId){
+      // cinny coalesces notifications by options.tag and carries the in-app
+      // route + real Matrix ids in options.data. Anything tagged goes to the
+      // rich WinRT toast (coalescing + click-opens-room); only a real room id
+      // gets a reply box. The tag is NOT a room id — thread toasts tag
+      // `room:thread`, invites 'lotus-invites' (cinny-desktop #17).
+      var data=opts.data||{};
+      var tag=opts.tag!=null?String(opts.tag):undefined;
+      var roomId=data.roomId!=null?String(data.roomId):undefined;
+      var threadId=data.threadId!=null?String(data.threadId):undefined;
+      var path=data.path!=null?String(data.path):undefined;
+      if(tag||roomId){
         window.__TAURI_INTERNALS__.invoke('show_rich_toast',{
-          title:String(title),body:body,roomId:roomId,path:path
+          title:String(title),body:body,tag:tag,roomId:roomId,threadId:threadId,path:path
         }).catch(function(){});
       }else{
         window.__TAURI_INTERNALS__.invoke('send_notification',{
@@ -519,6 +524,7 @@ pub fn run() {
             native::chrome::window_start_drag,
             native::chrome::window_close,
             native::toast::show_rich_toast,
+            native::focus_assist::get_focus_assist,
             native::hotkeys::global_hotkeys_supported,
             native::hotkeys::set_global_hotkeys,
         ])